Glue, Tape or ? to attach a light weight solar panel?

I have a brother that works for 3M. He gave me a roll of their high strength tape and said it would be fine with my 100 watt panel. Me being an engineer used the tape under the feet and then covered the top of the feet with Eternabond. 2 years later I still have no doubts it is on there for good. Hope I never have to remove the panel from my fiberglass roof.