In the past, I've had good experience with spraypaint, but considering I'm in a studio apartment not on the ground floor (and dealing with bigger tanks), I'm gong to try the latex paint. When I was in Home Depot, they had these little ~7oz sized trial for a couple dollars, that you can get tinted (I got mine black). container says it should cover a 4x4 area, which should be enough for 2+ coats on most tanks.
I saw those two but if I remember correctly the tints were darker than I wanted?
The 1st coat is the most important color wise when you use latex. If it's a bit too dark the 2nd coat use white. I had to to cross hatch my layers as I let the paint get to tick. I painted out doors in July and I should have cut the paint with water. I didn't get the smoothest finish. Still turned out O.K.