Autometer 5" Tach Mounting Question

[monte0185]

Im swapping all my gauges for Autometer gauges and since I already had a 5" tach mounted on the dash I figured id just move it to the cluster. I thought I would just take the mounting plate off and use the bracket to hold it in but i had to cut the whole backside of the bezel out for it to sit flush. Now Since my tach is the 5" big section and the smaller 4"ish section where the bracket for the dash mounts Im at a loss on how to hold it in the bezel. Best I have come up with is a couple of hose clamps put together so it has 2 places to hold it flush in the beze and then maybe some 2 part epoxy to keep it from turning. Anyone got any other Ideas or run across this before? Here is a pic of the tach I have. Ill take some pics tonight. Of the actual Setup.