I don't know about the Autometer gauges (never had them -they may be longer / deeper) but with the the Isspro gauges I was able to use the brackets that came with them to mount the gauges in the pod although I did "trim" the studs.
On mounting the gauge pod above the rear view mirror:
Did not have the fit problems you are having - Needed some triming to get the pod to conform to the head liner - but no problems with the mirror or it's brakets.
I used the velcro double stick tape and it worked o.k.
A worker at a custom car shop dropped my head liner and built a bracket that attaches to the same brakets as the overhead display - so the double stick tape is no longer needed.
Diesel Manor sells paint that matches the interior DieselManor - Accessories
Good luck,
George
On mounting the gauge pod above the rear view mirror:
Did not have the fit problems you are having - Needed some triming to get the pod to conform to the head liner - but no problems with the mirror or it's brakets.
I used the velcro double stick tape and it worked o.k.
A worker at a custom car shop dropped my head liner and built a bracket that attaches to the same brakets as the overhead display - so the double stick tape is no longer needed.
Diesel Manor sells paint that matches the interior DieselManor - Accessories
Good luck,
George