I'm planning to go with heavy gauge 1.125" diameter rings. Unfortunately I haven't been able to wind my own very consistently so prototype testing is being done with a salad of wire rings and tie wraps.
So far the only ring I like is the one big 1.125" one that I've got. I think I'll get them painted bright red as the red tie wrap rings we used last night were easy to find on the floor.
Want nearly free GBB gas?