Right now I'm working on a set-up that will have a supernova as a back up to one of three swords (the sword will be either a DA, Acheron, or BTB; depending on what the enemies are). Right now I have an Avenger, Silent Nightblade, Snarble Barb, Mighty Cobalt Helm, and a Miracle Cloak (soon to be a divine mantle). What do you think, good or bad system?
So your armor is on the path to being:
* Azure Guardian Helm
* Divine Mantle
* some shield left unspecified
Skolver Cap would be far better than Azure Guardian Helm. And Divine Veil with Skolver Coat would be a bit better than Skolver Cap with Divine Mantle. It is not too late for you to switch to better armor paths. (Most of the cost in making a 5-star item comes in the final upgrade, from 4-star to 5-star.)
You want to carry one sword and one gun. Your taste in swords is excellent. The big question is the gun: normal or elemental?
The argument for elemental is that swords are weak against turrets, so you want to use your gun against them, and all turrets are vulnerable or neutral to elemental damage. Also, non-normal damage types are generally preferable to normal, as long as you have more than one non-normal damage type on you.
The argument against elemental is that when you are carrying your elemental sword, you don't also want an elemental gun (except perhaps in FSC). If you're going to go with a normal gun, then Valiance is generally preferred to Supernova, I think because the bullets of the latter are so slow.
Here are my proposals:
(A) Valiance with any of those three swords
(B) elemental gun with piercing or shadow sword; when you want to use your elemental sword, go double-sword, no gun
(C) get a third weapon slot and carry two swords and an elemental gun