"Anyway, I can't seem to find any clinchers that to me look retro enough. I've gone back to the old tires which are Cycle-Pro Discoveries size 700 20C, and they seem just right, but are getting a little old. Any suggestions? The rims are Regina 1320s"
Suggestions: Vittoria has a whole line of clinchers + tubs. I've been looking at the online reviews and many are well regarded with low rolling resistance, longevity, and durablity. They have retro styles I think look nice.