If using mild paints, I think you could apply masks very quickly with post-it notes to get some colors on those panels. I've not painted anything sci-fi since I did an X-wing back in 1979, but it looks like you have nice raised areas around those panels that would let the post-its work for you.

Post-it notes will not save money, but they could be a super-fast way of masking out a few hundred rectangles without going nuts. You'll need scissors of course