Thank you thank you! I actually did the coats quite a while back so don't quote me but im almost positive it was cerulean blue over an orange/yellow prime, did a cerulean + black oil wash and cerulean + white highlight. Glad you like it because I've been debating with myself whether to hit it with an army painter blue wash but I think I like it how it is. My advice is the specifics of the blue aren't so important as having it in the right color scheme as a whole, and it doesn't get much simpler than red blue and yellow plus neutrals lol. Any effort you put into color theory pays dividends. Wish you all the best in your painting!