I went with some 5/8" delrin rod and made a three point mount using the stock RR, fuse holder, etc bracket in the stock location. Measured the stand-offs on the stock plastic, cut some spacers, and ground the ends to match the body contour. Attached the spacers to the bracket with the stock screws. Drilled through the body and into the spacers, then ran in some screws. One I through-bolted as it was a bit short for screws coming in from both ends. Worked about as well as could be expected. Ended up a little higher than stock so I could secure it to the race body on relatively flat areas. Might even work.