The yellow one was a repaint, had chrome, got as a frame in about the same condition as yours. Had some of the parts and still looking for a set of brakes. The silver one was repainted by someone else, had few of the Zeus parts left, but it was cheap and I found a guy with a complete set of Zeus parts he sold at a fair price. I added the decals to it. The red one is original and complete and found on ebay. The red one is early 70s I believe, the other 2 later 70s. I had a copper one I sold that had a metal headbadge, I'd guess those even earlier. In the late 70s they came out with a more highly developed line of parts, but I know nothing of those. I'd guess ones with chrome were the higher end models. You didn't see them around much in the 70s, but there sure seem to be a lot around now! I think they're pretty cool and different.

Almost all my bikes are 5-speed, maybe a couple of 6-speed. I typically use 14/28 Suntours from ebay, though the red Zeus would only run a 24 for some reason.