I forgot to reply to this because of the Ridley stuff, sorry!
First, thanks for the support! And thanks for understanding why we can't get to the costumes, hopefully the recolours we put in place are a worthy substitute.
For recolours, it's mainly a sense of what works with what, and being careful not to saturate things too far, and keeping the colours believable for the character. Shun actually wrote up a
short blog post detailing what went into the new Green Ganondorf, so hopefully this can give some inspiration. We actually tried a more golden "Dio-dorf" costume originally, but that was shot down pretty quicly because of how the colours didn't really fit Ganondorf. We actually go through a lot of renditions of our colour schemes before we settle on a final, so even if you don't get it right the first time, try again!
I can't offer much advice other than that because it's really mostly sense, so you'll just keep going at it and you'll get better as you go (this applies to everything!). Aside from that, practice your masking to make sure the right areas are properly coloured, and that's about it.
Some of us have said we'd maybe stick around, but me and Shun personally are done when this project is done. We want to leave with the best content we can, so we're working hard to finish all that we can with our quality standard. I'll probably drop by every now and then, but I don't think I'll continue to contribute.