On my boat (28' S2), I carry my dinghy on deck and its sorta hard to
see over, but........

My original backstay had a piece of wire cable spliced into it about 6'
off the transom with a stainless clip on it. I am not really sure what
it was for , maybe in lieu of a topping lift to hold the end of the
boom up. When I had a new backstay made, they copied the old one
exactly so I still have it. So........I want to make a chair suspended
from this attachment allowing me to sit in comfort, high enough to see
over the dinghy, steering with teh tiller extension. The chair would
rock with the boat. Any thoughts on how to do this?