I'm pretty sure how red is handled is a tossup. I believe placing 1 unit on Red is exactly equivalent to placing 1/18th unit on the 18 various red-# bets. In both cases you win exactly 1 unit if any of 23 spaces hit.
I think I know why you think there is equivalency here. There are 16 red singles, not 18. So, placing 1/16th of the unit on the 16 red singles wins 1.25 units (35*(1/16)-15/16 = 1.25), not 1 unit. Thus, there is no sense in betting on red color. Agreed?
