Mounting bimini

I'm philosophically opposed to drilling into fiberglass, especially with the number of pieces of hardware necessary to mount a Bimini. However, I've got these great grab rails, both aft, and fwd in the open bow, in which to mount a hinged Bimini clamp. But my grab rails are one inch OVAL, so a traditional 1 inch clamp won't work. I can't seem to find any 1.25 inch units, which would be easy enough to shim with some clamp rubber. Ideas? Update...Amazon might have a larger size.....