Need help with caster adjustment

[gcsupraman]

So went to get an alignment today on the 1972 K20. I've been having steering issues with the truck for the past two years and finally bit the bullet finished replacing the last of the front end wearable parts.

The alignment machine shows the following for the caster:
Left Front 1.1 degree (spec 3.5-4.5)
Right front 3.1 (spec 3.5-4.5)

I am having a hard time figuring out how to find a solution - partly because one side is so far off from the other. I looked on diy4x4 and found a set of 4degree axle shims - but that puts me out of range. I don't believe I can run a shim on only one side either. I also know there is a caster shim set available that (I believe) attaches to the ball joint. Problem is, the maximum shim only offers +/- 1.5degrees of caster so my left side will still be out of spec.

The only thing I can think of is cutting the left spring perch off, adjusting it and re-welding it. I wouldn't even know how to pull that off unless I found an alignment shop that could also do the welding - otherwise we would just be guessing at the proper setting and that would get annoying and expensive quickly.

Any other idea or tips would be appreciated!

-Greg