As of right now, all the hats would have to be identical. I thought khaki might appeal to the most people as it's a nice neutral color Theoretically it shouldn't be too hard for individuals to dye their hat a darker color but I've never tried that myself. I've forgotten what the other available colors are, but I'll post them up once I find out again. Flex-fit wasn't an option with this company. Oh, and a trick I learned from my Aunt for keeping an adjustable strap in place if it's moving on you is to hit it with a few stitches of thread.
Tomorrow is my last final, so later this week I can pick up where I left off with research. I never did hear back from the cap company directly. :(