A continuation from my first POST about this subject
I got the panel mounted tonight. 3M VHB tape and some angle iron. Seems to hold well!
The hardware is #10 stainless self-drilling screws with star washers from a local hardware store. I did add some 5200 around the connector once plugged in to help hold it down. I wasn’t confident that it would stay plugged in, or that the cord would seal well to the boot.