My XLab Flatwing system came via UPS. I was excited to install it. The Flatwing itself installed pretty easily. Just a couple brackets, and 4 screws, and I had it attached to the rails of my bike saddle. There were two positions that it could be mounted. I first mounted it the one way which had it a little lower than I wanted. So I mounted it using the other set of holes, and it raise it up a little bit. I need to pick up a couple bottle cages. I have a few of them lying around the house, but I would like the cages to at least match each other. :)
The XLAB X-Nut is a different thing altogether. I can’t figure out how to install it. The instructions say “For the FLAT WING, push the threaded potion of the internal socket head bolt through the open end, and place the star washer over the bolt threads. Insert and tighten bolt into the internally threaded section on the back of the Flat Wing. Use an accurate torque wrench set to 30 in.lbs to tighten.” Well those instructions SEEM clear, but the little allen head (internal socket head bolt) was loose in the package with the X-Nut. It wasn’t inside the X-Nut. The pictures I have seen show the threads of the allen screw pretruding from the X-Nut. But I can’t figure out how to get the screw inside of the X-Nut. I think it might have supposed to have been in there in the first place. There is a little threaded part where the inflator is supposed be attached. I am guessing the screw should have be inserted into the XNut before the threaded inflator part was installed. And I don’t want to try to remove it in case I damage it. I am going to try to call XLAB later today.
I haven’t installed the XStraps yet. They are attached by the screws that attach the bottle cages to the Flatwing. So when I get the cages, I will install those. I have read that people have had problems with the straps fraying quickly. They do seem kind of flimsy. I will try them. If they don’t work well, I can probably make my own sturdier versions of them.

Added:
I called XLab and talked to a guy there. He was very helpful. I was right in that the screw was supposed to be inside the XNut. He said it must have vibrated it’s way out. He was all prepared to ship me a new one. But he said I might be able to work the screw back in through one of the holes where the CO2 cartridge attach. I had tried a little bit last night and couldn’t get the screw in. I tried it again today while I was on the phone with him, and sure enough, I got the screw to go into place using a paper clip to push it around.
So tonight I will install the XNUT.
I stopped at the local sporting good store. They only had a couple bottle cages, but they looked to be heavier duty mountain bike bottle cages. I will stop by the local bike shop on my way home. I need another spare tube anyway.