Geoff (bluegtate) used some stuff from duplicolor. The can just says van/truck/car paint. First use some etching primer, then paint. About two coats of paint and 2-3 of clear coat from the can. Still holding up well and his paint goes near the exhuast outlet and still looks good over 1 year later. He doesn't ride as much as you do, but I think that it will hold up better than straight epoxy paint.
Bought all the stuff from autozone. You'll probably end up spending like $60 on paint.
I also did this on the square nose I just sold on the the sides after blending in the tubbies I sold.
Are you paint just the bottom sides, or the bottom bottom also? Seems like the paint would be gone on the very bottom after 1 month of pismo beaching.