Hi Jeff,
I used a peice of rubber cut out of a broken thong (hope thats what you call basic beach footwear) for the top of the main on Altered. You can choose the high density bits, just cut it very tight to fit your shackle. I love my push up mainsail wouldn't go back to a halyard if you payed me. Worth the bit of fiddling to get it right sometimes takes a couple of goes to hook up but found this with some halyards, comes down real easy.

Regards Gary.