You are likely going to need around three entire bottles of paint--it's a big kit.
Note that the decks, other than wood-clad ones, will be in Deck Gray. Gunship Gray tends to "scan" about right for new deck paint (and as a flagship, she's kept in good nick; there's 150-200 hands available 6 days a week to paint and re-paint).
The flight deck surfaces, when new, are a darker, near charcoal, gray-black.
NJ has a distinct advantage for you as the Museum ship, she has over 600 videos by her curator, and there are a number of nice close-in detail shots. There's a video specifically on all the "grays" used, too.