With you on the idea that 500 holes is too many! I had not figured how many that would be. I find it is often easy to think but it gets harder when we come to "DO".
Heat does make the choice of adhesives more difficult.
Some kind of industrial stuff like used on engines? Any idea how contact cement might do with heat? I suspect the expansion of the aluminum requires the adhesive to have some give to it to stay long term?
Thinking and looking at adhesives, would this be anything of value? https://www.amazon.com/Permatex-2590.../dp/B000ALDYPM
Heat and water resistant!