yodaforce
+1y
Problem number 1. to overlap it at approximately 75% like a real paint gun would be difficult to get it right without buildup, or runs. 2. Wetsanding it will make it look a little more uniform, but the can isn't really putting too much material on the surface as it is, and sanding is going to take alot of it back off. 3. The most important thing to realize is that spray paint does not hold up as well to the weather. It will fade, and oxidize and everytime you wash your car, you'll see it coming off on the rag. Which means you will be redoing it every few months or so, unless you keep it in a garage all of the time.
Regular urethane paints are made to be durable and withstand these effects. Spray enamels are good for your fender wells, underhood accesories, etc... not the exterior of your car. Same with most primers. It is merely a base for adhesion of quality paint, not to drive around for 6 months while procrastinating or saving for a paintjob. It will burn off and look like crap. Or, allow moisture to penetrate the coating and rust from the inside out. My honest suggestion is to wet sand the hood with 1000 grit (off the car) go to the paintstore, buy a pint of the color he wants (or to match the car), take the hood and paint to a painter at a body shop and ask if he can spray it on and clear it for a smaller fee (since all he would have to do is tack it off, mix it in a cup and shoot it, and probably clear it after he sprays another car with clear while he has some in the gun. I got a whole car painted for $50 when I was a teenager because I braught it to a shop and asked "Are you painting a red car anytime soon?) I had it sanded, bodywork done, and all they had to do was tape it off (not difficult because I had removed everything but the glass) and tack it off. Amazing what you can get if they don't have to do much.