X2 on the appliance paint. Cheap and works well.
As far as mounting the battery, I think Ralph Brunt had a thread were he mounted a tray on the inside of the stringer, which came out real nice. You could build a level platform on the outside of the stringer, glass it in and then mount a tray to that.
How bad is the gelcoat? It might just need to be wetsanded. Some guys have really brought the shine back to a boat by just doing that.
The split down the side where the rubrail goes, is normal. It's called capping the hull when that area is filled in. But most guys grind it out a little and lay glass down.
What are your plans for the boat?
The kona is a good hull. There are other hulls out there that are faster and handle rough water better. That is probably the reason guys are telling you to not put too much
into this hull. If you dump a lot of money and time into this hull, you might be disappointed if you try to sell for what you got into. But then again this is true with all boats

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If you do a search, you'll find answers and ideas to what you've asked plus, most any question you got.
Good Luck. And good job posting pics. We like pics
