Part 2:
Preparation for mounting the top shock brackets consisted of loading the trailer with water and other items as if on the road. The trailer was then levelled front to back so both ends of the equalizer on the side I was working on was the same distance from the bottom of the frame. I also measured the distance from the bottom of the axles near the hub before raising the wheels to remove them. With the wheels removed on one side of the trailer, I lowered and blocked the axles to the height measured previously (as if it were on the wheels).
To gain access, I cut the underbelly material at 45 degrees in the areas I needed access and then bent the under belly material at 90 degrees to the cut. This gave me a triangular access hole that was easy to close up later with tie wraps. The curb side was more time consuming, since the propane black pipe had to be lowered.
To position the top shock bracket to the frame, I used a 1/2 inch threaded rod that extended 13 inches from the top bracket (to simulate the normal ride length of the shock) down to the shock mount hole in the new spring bracket.
The top plate was then clamped to the frame and the hole locations were marked onto the frame using a transfer punch. Then I step drilled the holes in the frame (this was the most time consuming part of the install) making sure I did not hit any wires or heating duct by using a short piece of swimming noodle foam to hold the wires and ducting away from the inside of the frame where I was drilling.
After drilling the holes in the frame , I positioned the nut plate on the inside of the frame and bolted the upper bracket to the frame/nut plate. Before torquing the mounting bolts, I adjusted the bracket so the threaded rod was aligned with the spring plate shock mount hole.
After removing the threaded rod, with the shock vertical, I cycled the shock ~5 times to purge any air before installing it onto the brackets with the supplied rubber bushings. Once the stud nut was tightened until the bushing was the same diameter as the washers, I added a second nut to act as a jam nut.
I repeated this procedure for the other three shocks.
The shocks are mounted at ~52 degrees which results in ~80% shock efficiency: