I'll come at it like this. The higher the resistance of the coil you have, the higher the voltage will be, but the current will be lower. The lower your resistance the lower the voltage, but you will use more current (amps). That's why most mods use wattage (total power) as the variable setting. Once you find the wattage you like, you can pretty much leave it there no matter what resistance your coil is.
Watts = Voltage x Amps.
Not really what you asked, but it's the best way I know to answer.
Cheers,
Steve