Vamo is an excellent entry level APV that will do what you are asking about. What you are talking about is called variable wattage or variable power. Not all variable voltage devices have variable power. The Ohm's meter on the variable power/wattage devices is what provides the ability to detect the resistance of the coil heads you will be using. Highly recommended. I do not, and will not own an APV that does not have a Ohm's meter, except for mechanical mods, which are not APV's, but that's a different conversation. The Vamo V3 will work on virtually any topper in the market place. They are fabulously priced. The best price for a kit, which you will need, is:
Found 32 vamo at FastTech - Worldwide Free Shipping
Several choices. Recommend the V3 in Stainless Steel. Very nice piece of equipment, Remember the kit. You need batteries and a charger for the device in addition to the topper and the juice. The Protank is excellent, even better when paired with an air flow controller:
Tank Airflow Controller
The AFC allows you to customize the draw. The Protank is notoriously "airy" but with the AFC, you can tighten the draw to match any draw you like. Highly recommended. Best to you!