I had a request for more details on how I built the "roll-tisserie".
The front and rear arcs are identical. I used a combination of 2x6 and 2x4 lumber and 1/2 inch OSB for the gusset plates. There are plates on both sides of each joint, attached with glue and a bunch of nails. The curve was roughed out on a band saw and smoothed using a 60 grit flap disk in an angle grinder. The curve is large enough that it really doesn't need to be all that smooth.
The front mounting frame is made up of 3 2x4s. One horizontal piece is bolted between the subframe mounts, and two mostly vertical pieces are bolted to the fender mount hole at the top, to the inner fender support bracket, and to the horizontal 2x4. The angle of those two pieces doesn't quite match the angle of the inner fender support bracket, so the 2x4 is notched a bit so that it will line up over the upper fender mount hole. The front arc is then bolted to the front mounting frame. I used bolts and large washers where I could, but in some places there wasn't access to the back side to put a nut on the bolt, so I did use lag screws in a few places. I used 1/2 plywood and small 2x4 blocks as spacers where needed.
Make sure the arc is mounted far enough to the side to extend beyond the body of the car at all points. Sight between the front and rear arcs when both are in place and make sure the body isn't sticking out anywhere. I think I put the center of the arc 4 inches over from the center of the car (towards the passenger side in my case). This also means that the car will want to roll back to its horizontal position when you tip it.
