I bought my panels from AM Solar. Their bracket has a small, maybe 1x3 area with VHB. Thats all they use on 'glass and metal but insists it be screwed onto a TPO roof. I thought about, but didn't, taping that "foot" to 4x4 gal plate, attaching it with VHB or Dicor and a couple of screws as you're thinking. I even though about laying Enternabond over that. But the rain was coming...it's the VHB and one screw overlaid with Dicor. I do intend to revisit it.
I'm wearing trifocals now but my hindsight is 20/20.
Bilsteins and Sumos front and rear...HUGE! FatMat and Hoodliner...HUGE!
Hellwig sway bars F&R, 235/85 Hankook ATM, alignment...HUGE!!!
Battery watering, 260watts Solar and BigFeets to make life easier.