The Warp and Death Guard (or the big 4 for that matter) Appearence Question!

[house_cawdor]

I have been working on some post-heresy Death Guard. I currently have MKIII armor from Forge World and the Death Guard conversion kits to model them appropriately. However, I am stuck on a few things...

1. What pattern bolter should they be armed with? The ones in the Chaos box or a Forge World pattern?

2. What backpacks should they have? It is stated in the fluff that heretics like the open vents (like the Chaos Marine box set has) but MKIII armor has a different set. Would they change out the backpacks or would they match the armor variant?

2. How much "decay" should they be modeled with? Time flows differently in the warp so how "tainted" by their patron god would they really be?

3. Should all of their armor have about the same amount of wear? Should they all have about the same amount of "gifts"?

[Grailkeeper]

I think you could easily explain any problems away with the fact they may have had to scavenge equipment at some point