If I were to make a Space Marine force that utilized Necron combonent (both in their physical conversions and in fluff) would it be better to use the Vanilla Marine Codex and Iron Hands CTs, or use the Chaos Space Marine Codex with Mark of Nurgle?
Wargear could be done counts as as and when needed, though Flayers easily match Boltguns, Guass Blasters match Heavy Bolters, and Synaptic Disintegrators can just be Lascannons.
This idea stems from a conversion I did a while ago, that I have since lost the models to, that combined excess Marine Torso fronts with left over Immortal/Deathmark Torso rears. Thinking on the idea of a rogue Techmarine managing to capture and place in stasis pieces of Necrons and Necron Tech to study and replicate using Imperial tech. The "Hereticus Excommunatus" status of the chapter itself is from the idea that the Chapter Master embraced this new technology, as it was equally powerful, and the absolute lack of chaos taint lulled the Chapter Master and his command that the tech would be safe for use.
Deciding which codex I would use would give me a better idea of what options I could include, and how the theme would be achieved.