3----shim, i would install the spring and make sure it actually leans befor i welded a shim in, but you could find a old thin leaf and cut it down
The difference between the two perch heights are 3/8". Alls I did was weld in a shim I made out of 3/8" flat bar. 5"x2.5" is all you need with a hole drilled/cut in the middle. The middle section of an old overload would be closer than a thin leaf.
