I also removed the temporary fasteners from all locations across the sub panel that had been drilled for adel clamps and installed nut plates. That took a while, as I had to get some slack in the main wire bundle to get in there as well as remove the GAD box to get to one of them.

While I had the GAD out, I fabricated some 1/8" thick spacers to go under the mounting flanges and move it fwd a little bit. The connectors come out of the bottom side of that unit and there was the potential for a conflict, which this helps. I'll eventually secure the wires coming out if it to the horizontal main trunk bundle, and taht will make everything high and tight