Bridgett,
I sketched the one in tha manual on big pieces of cardboard after hearing they are slightly imperfect. Then after cutting and fitting the cardboard, (had to trim one) transferreed the shape to particle board and made the final cuts with a Skill saw. No problems on fit. Some suggest using pipe insulation foam tubing over the wood so it is softer on the body. I put a 90" board between, about 24" tall, so the verticals are exactly at the center of the wheel openings. Seems to work ok. Finally, to make the body easy to move around, attached the buck to 2 furnature dolleys.
Hope this helps. Is this your car you are working on?
LNJ