HQ 75Pts
Canoness
Eviscerator, Purity Seals
I'm not sure why the purity seals are there, but consider a book of st. lucius and master crafing the Eviscerator at the least. This will give you a good T4 character killer, though keep in mind, she won't chew through infantry overly fast.
Other good upgrades are a Cloak of St. Aspira for 2+ INV and a jump pack for added mobility. Some also like to use an inferno or plasma pistol so her great BS doesn't go to waste, but either option is a good deal of points.
Troops
10X SOB 136Pts
VSS
Heavy Flamer
10X SOB 136Pts
VSS
Heavy Flamer
For just a few extra points, you can add in a flamer, which gives you even more power come divine guidance time. And of course, books of St. Lucius all around.
20X SOB 274Pts
VSS - Book of St Lucious
2X Meltas, Purity Seals
20X SOB 274Pts
VSS - Book of St Lucious
2X Meltas
Again, I'm not sure about the purity seals. Also, for such large squads, it may be a waste to ever fire the meltaguns on an armored target and waste 18 bolters.
Fast Attack
8X Seraphim 221Pts
VSS Melta Bombs 2x Inferno Pistols
Purity seals on the vet will help with hit and run rolls. And a book of st lucius to help with the ld checks.
Strongly consider flamers instead of inferno pistols. Seraphim have the ability to use flamers over and over again in a battle to great effect.
9x Dominions 233Pts
4xMeltas VSS Book of St Lucious
Rhino, Extra armour, smokes.
I'd seriously consider dropping this for another seraphim squad or exorcist. It may work, but experienced players will know to go after the Dominions early and often.
Heavy Support
Exorcist 150Pts
Pintle Storm Bolter
Extra Armour
The storm bolter is the price of another sister. That's reason enough to drop it.
1499Pts
8 faith Points
Possible Changes, reckon that swapping the special weapons of the 2 large squads with the two small squads would work. Not too sure what the hell to do with the Canoness, want to use her to support the main battle line, Chances are she'll only be able to kill a little before shes marty'd anyway. Might change out the dominion squads special weaps for flamers love the idea of divine guidance with this squad
CC would be appreciated.
The Canoness should be used to go after characters as she doesn't have the power to go after entire squads. With a 2+ INV save and possible S8, she'll scare marine HQs, or chop them down.
Books of St. Lucius everywhere, they're a huge help.
Consider eviscerators in the squads. Helps vrs armor and can also go S8 to kill T4 characters.