I think finding a balance between the grey and blue is key and then sticking to that through the whole trilogy. I don't think there's any point making distinctions between Death Star squadron and Executor squadron, etc. though they are neat ideas to explain the difference.
I'm confident they'll end up looking great. Not too blue, not too washed out.
The right amount of blue for me is so it has that 'cold' metal look, not the Kenner/Hasbro toy look.