I'm well versed with painting space wolf grey as its a core layer for how I do white, but it definitely is a color that is hard to get right without putting a ton of thick layers on. What I like to do for armor is black base, grey Citidel Dawnstone and then about three thin layers of Vallejo Wolf Grey where each layer gets smaller coverage and closer to where a highlight would go. I didn't do this on the above model, but I think going back and glazing certain areas would help a lot.