I replaced an external outlet cover and used the tape. I believe I used mineral spirits to remove the residue from the old tape. Washed it off and then put a coat of wax on before installing the new tape/outlet cover.
This could be long shot but could be the best solution. Hein makes profiled gaskets for fan van roof installations, he could make a specific gasket on his CNC machine assuming you have 3D drawing. Good luck. https://diyvan.com/