Restrict your current draw to 2.5amps or less. To figure that out, divide the voltage by the ohms.
For example, at 4.8 volts, 2 ohm carto draws 2.4 amps 4.8 / 2 = 2.4 amps.
Since the Twist goes up to 4.8V, a 2ohm carto will allow you to use the full range of available voltage without bumping up against the 2.5 amp limit.
Dual
coils will work o.k., but with a 1.5ohm Dual Coil, you'll be straining the battery pretty hard by the time the voltage is high enough to power the two 3ohm
coils inside.