Recently I installed 15x7 Truck Rally's on the horse truck. They came to me w/o trim rings so I began poking around looking for the "rounded" style rings that I feel look best. I started noticing that a lot of these old trucks have the car rally type rings that are beveled-for lack of a better term. But I didn't want to spend a lot of money on rings cause this truck is a part time drivers training rig for my teenaged daughters.
Low and behold-I walked into Kragen Auto Parts this morning and discovered they stock the rounded style rings for $12.99 each. They're cheap and they look good (from 5 feet away). The bonus is they didn't fly off on the way home.