I can paint a whole ody and all the parts with 1/2 pint. And thats two coats.
Can you find the kits local? If so buy two and return the other if you do not use it. Being this is your first time with por15 and the size of your project it will be pushing it.
Remember the first coat is feather lite. It should look like crap after the first coat. The 2nd coat goes on like glass.
If you can find it local then buy the 1/2 pint for like $20. The quart of marine clean for $12 and the medal ready for $12. You will also need a few cans of black top coat to spray when por15 is still tacky.
Por15 will look good and be strong on clean new shinny metal like you have. But do not expact the legendary rock hard without some rust. It's weard stuff for sure.
I would say the starter kit would do a small kids kart pretty easy. Any motorcycle easy. Your project is to big I am thinking. Even at $42 for a paint job is not bad. Gas nor anythng will touch it. So when you spill gas on your tank and frame no worries like cheap paint. Also it's still cheaper than buying am bunch of primer and paint rattle cans.
Also check into por15 hardnose paint. They have colors but it's a little more. This stuff is rock hard even on shinny new medal. The can says to tough to chip. And it is.