I can't believe I was making it so hard. The technical counselor helped get me on the right track. I think. I still have to finish installing them.

First step was to remove the six nut plates that are in the way of installing or removing the weldment. This will allow me to easily insert and remove the gear leg. I thought about this before but didn't want to go through the work of removing and then reinstalling the 6 nut plates. But that made everything else really hard. Now it will be easy to fit the part, inspect the holes, remove the part, file a little bit and then repeat until all the holes are aligned (without touching the precision holes in the spar carry through structure). Why couldn't I see that on my own?

It has been too long. At first my air drill wouldn't turn. I had to work on it some to break things loose. Now I just need to use it every day. I need to try all the other air tools...