RE> "What Paint"
There is no clear answer. I don't mean to quell discussion. I'm looking forward to hearing what others say. The Jamestown link you provided is no doubt a high quality product. It is pricey. $32 dollars a quart? Phew. It'd better be good. That's what two part linear polyurethane automotive paints cost. Automotive paint is toxic and it has to be sprayed on. Dealing with it requires acquired skills. I'm not necessarily recommending it. Just saying. I think that paint is also much the same thing as oil base house paint. Just a very high quality version thereof.
I've used much cheaper house paint that cost in the $40 per gallon range. It is not a durable as automotive paint. Not nearly. But it's cheap and oh so easy to touch up. Minor scratches in an automotive finish are a big deal to touch up. There are two part linear polyurethane finishes that call themselves "marine" that cost even more. But I've never been convinced those $60 dollar a quart marine finishes are any better than car paint.
There are other technologies too. I'm not an expert. Last time I used house paint. Yesterday I sprayed with car paint. At $35 dollars a quart. One nice thing about car paint is ten zillion color choices. With mail order boat paint you usually have to choose from a dozen deeply saturated one color colors.
To paint a Beavertail inside and out you'll need more than one quart. A quart might do the hull only. Probably would But by the time you paint seats and lockers too you'll need another can. I like to do the outsides with one color and the insides with another. When you spray the paint I used to like to do the inside with a much lighter color. Then, as a final step I'd reload the spray gun with the darker outside color and adjust the cup gun so it spattered widely space fat splots. I liked the way the darker splats of outside color looked on top of the lighter inside color. A splotchety finish like that helps hide flaws and lazy work too. Always benefit for me.
Haven't done one of those pock mark finishes in quite a few years though.