My boat (hull #231) doesn't have the fuse holders mounted on the wooden cross member. They're mounted on the cabin sole, next to the batteries, so they're not an issue when changing the batteries.
I like the 6v golf cart batteries. Had every intention of installing them, but my 4D's died while we were at anchor in Cape May, NJ. Had to buy new 4D's from Utche's Marina. Lucked out, though. They were a good price, and the manager and a helper (weightlifter) lifted out the old batteries, and dropped in the new ones for no charge. If you're gonna break down, that's the place to be.