Or are you talking about installing a strap from wing post to wing post so you can tuck your feet behind it to lean back while still seated on the wing?

None of the H17 sailors in Div11 have anything like that as they usually sail the boat sitting up-right on the wing and if they need more leverage they just hook-up and trap-out. I think they do as I do on the H18mag and tuck/hook my toes under the gunwales. But I have seen "footstraps" on H17 wings

Harry