Well, it all pretty much boils down to wattage..
More wattage = more heat..
Voltage squared divided by resistance.. So, say you're using a 2.2 ohm atty at 4.8V,
4.8X4.8=23.04.. Divided by resistance: 23.04/2.2=10.47 watts.
I personally like most of my juices at around 10-11 watts. if you know the resistance, you can figure out what voltage you would need to have a certain wattage.
Say you have a 3.2 ohm HV atty, and want to
vape it at 10 watts.. 3.2X10=32. Square root of 32: 5.65.. So you would need to dial the Provari up to 5.7V to get 10 watts from a 3.2 ohm atty.