Most say the target wattage for vaping is roughly 10 watts. Much higher than that and you may begin to cook the juice and not get very good flavor. So using a 5V mod you would not want to use a low res atty/carto. Stick to attys/cartos with an ohm rating above 2 for vaping at 5V and above.
E = Volts
I = Current (Amperes)
R = Resistance
W= Watts