Used the mount that got sent, even though it was the wrong one.
No screws, no adhesive.
Took a hotel room key, used as a heat gun to heat up the room key then curl the end kind of like a candy cane, and adhesive on the curl of the room key and the curl on the mount, and slide the part of the room key inbetween panels.
Put a green cap over the light, so gauge lights up green.
If I stay with this I need to find a aluminum cup to cover back.

I feel more comfortable with the mechanical gauge.