I'd forget about the aluminum grommet and use a rubber one instead. Aluminum will chafe on the cooling line where a rubber one won't.A rubber one also doesn't need any sort of glue to hold it as the fiberglass will be in a groove that runs around the outside. As far as what ESC to to with, I'd talk to Offshore Electrics on that one. They specialize in high performance electric boats Their website, with contact information is https://www.offshoreelectrics.com/