I also go with Rustoleum paint, but I use a $15 Harbor Freight HVLP sprayer and additives.
The "Secret Sauce" is adding a capful of Japan Drier and thin it with Acetone to get it to dry and cure VERY quickly, compared to without. The Japan Drier is a hardener and accelerator, and the Acetone helps to evaporate the solvents.
This mixture will give you a super-glossy finish that will be dry to the touch in an hour or so, and be a tough finish within a few days
That being said, it is VERY important to lightly sand with 400 grit and use a good aluminum primer first. Rustoleum makes aluminum primer in a rattle can that works well, but there are many others you can use. I use this one because I know they will be compatible.
Set your gun using paint thinner to get your spray pattern decent. Mix up your paint, use a straining filter, and then lay down a "dust coat", not trying for full coverage, just a light, powdery coat that you can see through. Let it flash off for maybe 2-3 mins, then do it again, this time going for better coverage. Let it flash, and then go for your first "wet" coat. Let it flash for 5 mins, then do another wet coat.
With a spray gun, it goes shockingly fast. I can paint the whole side of the boat in maybe 2 mins, if that.
I typically use 3-5 coats, letting the solvents flash off for about 5 mins in between. You don't want a lot of liquid buildup, but you also don't want it to dry too fast.
After it's looking good, go clean up your gun and mixing stuff carefully. This paint system will be dry to the touch in about an hour, and will actually be hard the next day. Still, I would wait 5 days in the summer before doing anything with the boat to let the paint fully cure.
This is by far the best system I have ever used to paint a boat or anything this is compatible with, for that matter. Some guys use this system to paint cars, and they look shockingly good. That is where I saw the instructional video, in a car-painting YouTube video.
I hope this helps. I'll never go back to a rattle can or brush/roller as long as I can do this.