Can't get Pro Parts headers to fit.

Schumacher sells a shim pack. The kit should come with a bunch of shims that fit under the mount. Different sizes which add up to over 1" of shims.

View attachment 1716172700
These shims look great!
I just hope that I can raise the engine enough before the header tubes that curl under the frame actually start to hit the frame.

Question: If I shim one side, do I have to shim the other side an equal amount? Or can I shim one side without touching the other?