Those are beautiful landing pads, nice job!
As a lifelong carpenter I can speak with authority. And, they could have an auxiliary purpose...dumbbells for that workout on the road!
My guess is that two pieces of 3/4 marine grade plywood glued together would be adequate and half the weight. I don't have jacks so this I know not for sure. And I'd put a longer rope or have a stick to position and retrieve them (as a ski bum my knees barely survived my previous life.)
Really all my PC is missing is leveling jacks (and liquid springs.)
