I have one of these machines, and have been slowly doing mods to improve it. I got a lot of ideas from your posts.
One thing I had on mine was that the stiffening strap on the back of the upper shear blade support was useless. With the adjusting bolt slacked off, my shear blades were already too close in the middle, and too far apart on the ends. Tightening the bolt, of course, just made it worse. I had to put shim stock behind both blades to get them so that I could have some tension on the strap and have the blades parallel. Works much better now.
For just a little more, you can do it yourself!