My car is disassembled for restoration, so I`m working from memory, but can`t you just lift the soft top lid, pop up the seat cushion, unscrew the backrest thumbscrew, lay the backrest on the seat cushion then install the wind screen? You should be able to choose one or the other, either the windscreen or the kinderseat, but not both at the same time.
My kinderseat takes about two minutes to remove if I remember right. I thought the windscreen was easy to R&R without tools also. Am I wrong?
Tom Kizer