A Smoktech SID is a great purchase. Great device that always hits like its brand new. As far a Voltage, that depends on the resistance of the coils in the tanks. A rule I use is double the resistance, then go up by around .3 or .4. For example, I have an iClear 30s, and using 1.5 ohm coils, I vape on 3.3-3.6V. With wattage, I like to mess around and find what tastes best. It's different with different tanks/coils. On the iClear, I can use between 12-13 without burning the coil.