Hi,
My 2001 Bav 47 cruiser has had the joint glassed in 2020. They used 3 layers of fiberglass and filler applied into the joint (polyester). I'd strongly advise you to apply more than one layer of fiberglass, you'll add strength to the joint, avoiding premature failure, as the hull will flex under load. Adding further layers once you've gone through all the trouble of removing the deck hardware is no biggie.
As my teak toe cap is partly rotten, I'm now planning on further upgrading (in my eyes) the toe cap to aluminum. That will remove some flex from stanchion bases and make them waterproof for a longer time.