I took a final decision on the gauge to make the shim for the roll bar feet that rests under the front of the passenger side rollbar.
Cut a rough shape out of scrap aluminum and fine tuned it under the roll bar feet. Then tapered it on the belt sander.

Then marked the sides of the roll bar feet in relation to the canopy decks to cut off excess material.

After smoothing and sanding one side.

Cutting in action using a regular cutting disc in the die grinder on the opposite side.