I'm doing the same thing with my Ultramarines.
They were the army I learned to paint on, and they're pretty rough looking. Some of the faces are just a blob of fleshtone paint, and look like they're from a Cronenberg movie.
I thought a 'Reto' inspired scheme with a super vibrant blue and those 'goblin green' bases would be pretty fun.
The trick is just sitting down and getting the work done, because I absolutely need some kind of deadline to stay motivated.
Over the summer, I bought a Warlord and got it built and painted in the span of 3-ish months for a gigantic, unlimited Apoc game.
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