I’d suggest that paint, especially the underside, is NOT important. The fish might appreciate seeing a nice white finish but I’m not concerned about the fish view. The inside painting?, Only if it’s really irritating to your eye.
I kinda like the look of the new modification wood being the epoxy finish… maybe just touching up the white that was removed. The goal, for now, is to get things set for your great sounding trip with Avocet to Florida for sailing adventure. Paint can wait. Just saying’.