Didn't make a lot of progress this weekend, but I got a lot done. When I tested the Retracts I was having some issues, so I had to dive in and resolve everything. Here are some things I noticed that you should check out.
The set screws have nice flats on the shafts, but not all of them have Loctite or are even tight. Don't forget to Loctite and tighten them all (standard practice).
If you use the mounting screws provided with no washers, they are a bit long. Be careful you don't tighten them up and damage the surface of the wing. I shortened mine.
The retracts may hit on the fuse when you slide on the wing, make sure you check for clearance and grind away what's needed.
One of the pistons hit the wing skin when the gear was cycled causing some binding. A little bit of grinding on the corner of the piston, and a bit on the inside of the skin (being careful not to go through) fixed it.
The air cylinders come apart, but the caps were not tight as delivered. That's fine, because as you'll see on the next comment I had to take them apart.
Most important: When cycling there were times when the gear would hang up and air would leak past the cylinders. It wasn't all the time, but enough to worry me.
Upon investigation it appears the groves in the piston are a bit deep for the o-ring provided. A trip to the hardware store and I found slightly bigger o-rings that solved the issue. The quality of the pistons and the way they come apart was excellent. Now that I have the correct O-rings I'm confident that the gear will be reliable.