Thanks, may need to get a few. But how many can you put in? It looks to me like the top of the wheel has to move about 2cm.
A shim has an exaggerated effect, a couple of shims is easily a cm at the wheel. The bolts are long enough you can get several shims in if you need to.
But if it's too far out of true, there may be something bent or damaged in the subframe or wishbone carrier. Or it may be a victim of uneven lowering as every inch you drop the car gives around 2.5 degrees extra negative camber.
However i've seen a car with a single shim on one side and 4 on the other and it looked and drove OK. Just Typical BL build quality and high tolerances they had in the 70s.
Also, sort the balljoints and other problems first, no good setting it up till everything is correct.