I personally prefer the antenna on the hull not the deck lid. The aluminum antenna holder (you can see it in the pic i posted last) is really strong /watertight compared to the rubber grommet. I just drill a hole to the exact size of the thread on the antenna holder and use silicone and a rubber washer and screw it in.
what ever works is the key tho ,if the rubber grommet works then use it.
It was 4ft and blowing off shore here this morning i couldn't help my self, the dudette stayed in the car!! hahaha