Good choice! That is a huge jump from a V2 to a Provari. I started at a V2, had a few in between then finally landed on the Provari and to be honest it could be my one and only ecig. It is magnitudes ahead of most other ecigs out there let alone a V2 lol. With your Mini Vivi Nova, you will probably want a higher resistance head, like 2.4 or 2.8. There is even a 3.2 for if you get into higher voltage vaping.
You'll know you have the right atomizer head on, for a few reasons: 1 - the Provari flashes an error code at you if the resistance is too low for the voltage you have it set on. 2 - the juice doesn't taste right. For example, I was vaping a chocolate today at 5.0 (chocolates vape at a higher voltage), then swapped to a blueberry lemonade without changing the voltage. The lemon in the ejuice felt like it was BURNING my tongue! I dialed back the voltage to 3.6 and it tasted like sweet blueberries again.
When you have an idea of your target wattage, you will choose your resistance atomizer head, and set the voltage to match and equal the target.
As per the posters above, it's the wattage that determines the sweet spot for a juice. But you don't have to sit and calculate Ohm's Law, you can use the chart, and you will also get familiar with the Provari as you use it. Again, be sure to check the Atomizer read out often, and set the voltage accordingly. The actual resistance won't always be what is printed on the head. Once you are more experienced, when you jump from the Vivi to an RBA the Provari will really blow your mind. I am blowing out PLUMES of vapor right now on mine with a Cobra; I build the wick myself from ss mesh and wire, and tweak the resistance as I wish.
Fruits = lower wattage
Chocolates, tobaccos = higher wattage