Vog, no question.

The fiend bonus from Veil will only apply to Trojans, and 90% of the enemies in FSC are undead, so that bonus is essentially null. The piercing defence from Skolver is next to useless shy of the very few jellies and wolvers. The shadow def is useful for zombies, but they're generally easy to avoid and are not the greatest threat.
Firetiles and firegrates deal elemental damage, puppies deal elemental; they'll cause a lot more damage than a stray zombie swipe; not to mention that you'll only have half shadow defence anyways.
Normal def (which you'll also only have half of) comes from trojan slams, spikes, firetiles, slags, vanas mace. All things that are pretty unforgiving.
The biggest threat will probably be actual fire status; FSC fire is strong and will last around 8/9 sec with no resistance, dealing about 2/3 damage per tick. Divine Veil gives you half resistance, so that's something.

Essentially, you're sacrificing a useful defence, vh:asi and max fire res for an all-rounder set which gives only med:dmg, half resistance to scary stuff and half resistances to stuff you won't encounter at all.

All-rounder sets are good don't get me wrong, but when your decision is about a specific dungeon, the all-rounder falls to pieces.

Vog allows fire to end in about 3 seconds while dealing little damage and offers high protection against prime threats in FSC. The only drawback is that you will have to be that bit more careful around zombie attacks, as you will have no shadow defence.

Also, Gray Owl is a good choice. CoA is also widely used for FSC. Both have fire res and decent normal defence. Only difference is the special type (which doesn't apply as much to the above statements, since it's shielding and not tanking), however I'm guessing from the very nature of this thread that you don't yet have the tokens to craft a CoA anyways, so this is fairly pointless to say...

full vog. of those choices, anyways. it sounds like you're relatively new to t3 status, what I use is probably not an option considering it takes savings

I use full snarby with max fire resist on the coat and high on the cap if I'm solo (where I use a swordy weapon assortment), the snarby cap+ shadow max volcanic demo for teams (as designated shiver-er)

either way, fire resistance either by uv's or natural is the most important thing to have (imo) over damage type resistances (shadow/ele/etc)

I would suggest a different shield, though. No shield is going to stand up to more than a momentary graze of the fire pits, spikes, or file tiles. I would say to get the blackened crest>CoA since you'll probably use your shield for zombies/trojans/slag guards the most

Assuming you can't afford to build two sets, then Divine Skolver would suit you well, as it'd let you roll everywhere you wanted across a variety of missions. It is usable in FSC but you'll find yourself hurting a lot with it. Using Vog outside of FSC is also usable with the ASI bonus but any areas that don't deal elemental/fire will make you feel fairly naked; then again the ASI can always count for a lot to help keep you up to pace.

Take the Skolver-Veil Set.. It is reliable for FSC and also your general clockworks run. It works great in LD too, the shock helps and if you somehow add shock resistance on your Skolver you will block all those VT, Storm Drivers and Polaris. Well it all comes to your choice.