Subframe Install Images - docschops
This is how I attach the Dime Dity seat to my frame, 3/16 alu rivets, 1/8 x 1 1/2 alu flat stock and a 3 inch piece of alu angle

This is how I attach the Dime Dity seat to my frame, 3/16 alu rivets, 1/8 x 1 1/2 alu flat stock and a 3 inch piece of alu angle