Well, if you're vaping a Joye 510, the atomizers are about 2.3 ohms. And you wouldn't want to go any lower than that for fear of killing the battery. And of course, the higher ohms will kill your vapor. The Joye 510 only puts out 3.2 volts.
I've been playing around with a 801 atomizer and 510 adapter. The atomizer is rated at 3.5 ohms, but it seems to be working pretty good on a 510. The 801s work better at lower voltages. I know MadVapes sells a Bauway 801 cartomizer (and for that matter, a 510-801 connector adaptor) that gets good reviews. If you're playing around with different options, you might consider trying it. They do make your e-cig pretty long, though.