The XADAPT2 works as designed. I ordered one to install a 1994-era Thule 599 Upright Bike Carrier (predates the 599xt and 599xtr Big Mouth carriers) onto my new Thule Aeroblade load bars. Earlier, I installed the Aeroblade load bars and 480R Rapid Traverse Foot Pack onto my car, so now those adjustments were already made. Later I took the bars off the car until I was ready to try the upright installation.
I placed the bars with foot packs across a couple of wooden chairs in sawhorse fashion, which was much better than working on the floor. I printed the XADAPT2 instructions from the Thule website, laid out all my parts, and went to work.
The XADAPT2 contains everything you need. Fortunately, the Thule mounting plates have stayed basically the same since the original 599 upright. The cam handle (lever) that came with the XADAPT2 is slightly different from my originals and actually easier to clamp down. You don't have make full 360 degree turns as you seek the right clamping pressure like the earlier design. This is especially helpful because the XADAPT2 spacers add enough shim height that the clamp is either too tight or too loose. With the 180 degree turns you can get the right amount of clamping force without risking damage to the Aeroblade bars. I like this newer style lever so much that I was able to order some to use on the front plate.