Something to be aware of: the fire aura granted by a Psalm-Doctrine works server-side during the in-level dialogue sequences. Which is kind of an exploit, although a pretty funny one:)
Oh, I'm going to use it with all four characters, that I have:
1. It's great for a Heavy Flamer Crusader.
2. It works wonders for a dual Arc Blade Assassin.
3. I expect it to be a solid investment for an Empyrean Psyker.
4. I expect it to alleviate the Tech-Adept barrel woes.