Here is my report on my quest to improve the ride on my 1946 GMC 1/2 ton. I am happy with the results! I outlined the different steps I've taken in the initial post. I went to Home Depot and bought some C-channel and made some mounts for the front shocks. Here's a picture of the result.
Shock mount for tube shocksThe total cost to make the mounts was $14 for the steel and $44 for both shocks from RockAuto. I used the stock mounting holes so I didn't have to drill anything. I made a lower mount out of 1/8" steel. If anyone wants more info I can send my plans. For the rear shocks, I simply bolted a piece of angle iron that runs from frame tail to frame rail above the old shocks lower mounts. I drilled holes in the angle iron and used the stock lower mounts. The rear shocks I used were Monroe 31125 that cost $16 each. You'll notice that all the shocks had a stud mount (the end of the shock is just threaded) and that simplified everything.
The ride is much better and less harsh. The old knee action shocks only dampen on the rebound, not on compression. The new shocks also seem to dampen the body roll when going around corners.