Hi Dave
If the difference between “to clamp or not to clamp“ is small, I usually cut a strip from an aluminium beer/soda can and roll it to a ring. This ring can be placed between the clamps and bar (avoid overlapping the ring).
SOFT aluminium is good to use for shims in some other applications too, as the ally surfaces adjust to the surfaces it squeezed between, and grips very well.
Best regards
Leif
