Yeah, I prefer dropping fire just to leave DoTs on crowds, shock would be much nicer for the graviton combo, but my VT is still only 4* (can't find the recipe anywhere :( ), so I tend to find that Ash works nicer, just from easier placements. Sayin' that, for solo bombing, it really makes little difference which you use; the fling effect doesn't bother me too much because they all fly straight back towards me and funnel into the new vortexes.
For solo, definitely.
For groups it tends to be a bit trickier, if people aren't aware of the strategy, VT does tend to be better in group work.
When I get my VT to 5*, i'll definitely be using that more often though

EDIT:
Holy crap, I rambled on far more than I expected e.e....
TL;DR?
Took more damage because I was wearing the wrong set, mainly. Wasn't focussing on a perfect run, just getting the footage. Will next time.
Confined areas are dangerous for bombers, they need to move around a lot. Vortex solves many of these issues.
Single giant lichens; use nitro, guns, swords, not vortexes/hazes.
Slime spikes are a dastardly attack in RJP/Slimeways that you grow to forget about with vortexes making your life safe; keep them in mind.
Vortexes will never interrupt attacks, so time carefully.
Plant vortexes by ducking in and out quickly, timed accordingly.

Should really have recorded this in my JK Loadout, woulda made more sense..shame I wasnae thinkin'! Next one I'll put more effort into it beforehand; this was honestly originally meant as a "get in, take a shot of a vortex, leave". x.x

@Bopp:
My hp was quite low, as I stated in my OP. I did screw up a few times and wasn't carrying my proper armour loadout, so my damage intake was far higher than I was actually used to, which threw me off a bit. When I use my proper loadout it's very realistic (even solo) to walk through the entire RJP with minimal contact.
The two rooms on the right in Runaround are kinda tricky as a bomber as you're left with little space to manoeuvre , but I find that vortexes are always the answer to confined spaces, dragging all the mobs into controlled grouping.
Giant lichens, are tricky with pure bombs; Nitro actually does a very good job on them (and, in my experience is probably /the/ safest way to kill them, short of well-used guns) but takes a lot longer than swords. On that video I did use my FoV to finish him, but using the hazes to drop shock/fire can and will speed things up for you. Vortexes can be used to keep him in a corner or something, but otherwise have limited use against a single giant lichen. The main goal is usually to damage him as much as possible while you clear the other mobs, then bring out the utility sword or nitro.

@Fradow...or Bopp, I think...replying..at Fradow...to Bopp? Idk! D:
Spikes are generally the problem yeah, especially in the first checkered spike room to the left in the Garden; a bombers primary objective to keep on their toes at all times, stopping is never the answer, so in an area surrounding you with spikes and forcing you to stop, generally is when you take damage, unless you're good with your utility sword.
As for Slime Spikes (which I just realised that you probably meant that to begin with!) yeah, I definitely find them the trickiest of all mob attacks (even lumber swings can be avoided while charging vortexes), becuase any of your bombs will obscure it and even the charging bomb above your head can make them harder to see. The main issue is that I focus all my attention on where the vortex/mobs are, and where they're about to be. I can do this because generally all mobs are in the vortex and you're otherwise unattackable, but in RJP/Slimeways they can sneak in Spikes underfoot, and I let myself get caught by that more often than I'd like to admit.
Hazes would cause more problems in RJP, but I never tend to use them in an area that would obstruct my vision much, I like dragging things away to vortex them, so that issue can be avoided.

Spot on about the vortex though; a mob that telegraphs the attack *right* before they get sucked in, will continue the attack and unleash it at the point. This is also true for when they're inside the vortex and get thrown outwards; the vortex will do nothing to interrupt attacks at all, leading to some timing issues.
The trick is generally just to duck in and out and in and out. Have the bomb charged and drop the bomb right *in front* of their faces (so when they move to chase you, they don't pass it completely, ofc), then take a hearty step back to avoid attacks. WHen the next bomb charges, duck in and place it square in front of them again, leaving little/no room, and run back out of range.
You can see me timing this badly at the Scuttles on the mech mile and the top-left room in runaround, where I respectively walk in right as a scuttle attacks, and stay in the rad for too long and get caught in the suction (which is a potential killer in T3). Gotta just get in and out fast and you should never take any damage.

@Tom:
My shock haze is only 4* still, so the rad is far smaller. The 5* VT is the same rad as AoA, letting you freely choose depending on the situation. I enjoy fire for solos, but shock is safer/more group-friendly for teams

They definitely are. To be brutally honest, I wouldn't even bother using the 3* one, the damage is low, the rad is very small and getting it to +10 for teh CTR won't be worth it.
However, the 4* versions are usable. I used my 4* vortexes for a long time before I found the 5* recipes and it played very well for me. The damage difference is noticable, but on a small scale; it won't slow you down much.
The real difference is the vortex size. The rad size doesn't actually show up as any larger/smaller between the bombs, but when the graphic plays, you see that the gravity effect reaches far beyond what it shows.
However, this is to a degree that it's generally redundant unless you're planting the bomb in the centre of a room, and running to the side.

By planting bombs at choke points and when you have mobs congo-line'd, you'll probably never notice a major difference in the rad size.

Basically, they get used in the same ways, you just have to be slightly more accuracte with positionings, and have to risk yourself a bit more when planting in their face. However, odds are you'll never notice a problem until *after* you've got used to using the 5* version and go back to a 4* one. When you've never touched the 5* bombs, the 4*s are just fine, it's all about what you're used to :)

Don't let anyone tell you otherwise about vortexes btw. Electrons are more popular because of the shock, but against slimes/gremlins, Graviton has is a real difference in damage that pays off (letting you use fewer bombs).
Anyone in a party will love you for using vortexes because of the all-round benefits they hold, so never let someone tell you that "vortexes" aren't worth it, or can't be used for damage or any such :)

The difference in damage is neglible in larger parties, people love vortex in a group due to its utility and although vortex damage speeds things up, a few well timed max dmg charge attacks from your team and often whatever is in the vortex is dead irrespective of the vortex damage itself. The damage difference matters when soloing or duoing, but in larger groups your party isn't going to explicity express any additional joy due to you choosing Gravi, especially when the shock from Electron has immense utility in making sure mobs don't get flung all over the place if something doesn't go quite right.

I should have been more clear on that, yeah; in 3~4 man parties the damage difference does still apply, but typically is mitigated simply by people taking the vortex'd group and attacking them outside the rad before the 'splosion.
Solo/Duo (the way I usually play, just me & my gf, so I tend to bias things towards that) the damage will count for a lot more. If you're using statuses during/before the vortexes, then losing out on the electrons shock should be irrelevant, if you already dropped a VT beforehand. Especially useful if your party uses sword weapons that don't KB them out of the vortex, but that's terrible for PuGs; good for guilds or friend parties though, that are aware of the overall tactic.

EDIT: Oh! Just realised what you'll have been on aobut, the "will love you for it" bit, I expect? That was a comment more on vortexes as a whole ("anyone in parties will love you for using vortexes") and I just re-read that and realised it came off as me saying that the parties would love you from the extra damage; total wording fail on my part; will go edit that!

Bombing Guide up on the wiki. I expect more videos in the future, you had better not dissapoint!

Steam users can't edit the wiki, afaik (correct me if I'm wrong, ofc). I was just gunna wait till I'd made a few videos and just make a post somewhere and update it, let it necro away and link it when relevant, but poppin' them in the wiki works too! :D
And I definitely intend to make more, t'was great fun puttin' that together, altough it is pretty patchwork, considering it was all unintended and just wound up accidentallying itself into a full-blown guide! xD
Next one I make will hopefully be more carefully planned out, and come together nicely; already got my plan for what it'll be :)

Edited my last post, realised I might have misworded somethin' and caused confusion.
As for the format link, thank-you. Only took seeing the link for me to be able to find the link myself! xD

Oh yeah, s'easy to do RJP with vortexes and keep damage to a bare minimum. I'll do a run later and grab some footage of my proper loadout for it. The Fraps recording still lags me, but I'm sure I can push through that still w/o too many problems.

But given no lag-related complications or general laziness, using vortexes can be extremely safe, if you keep an eye on their attack telegraphs. With everything bundled into a vortex while you stand nearby, nothing can ever really get a hit in unless you get too close, or improperly time stuff.