Kind of depends on the type of Vape you like.
Typically, LR atty's (1.5, 1.8) produce a warmer vape vs. 2.0+ type atty's.
The nice thing about the Provari is its versatility. It can pretty much handle any atty, whether it's 1.5 or 3.0 .
When I first started dripping, I picked up a 1.8, 2.5 & 3.0 atty. I've been finding that I tend to favor the 1.8 atty and the vaper, flavor and throat hit it produces.
If you're already
vaping with a clearo or
tank, you could try picking up an drip atty that matches the ohms in those
devices as a starting point. Then, in time, pickup a couple of atty's with lower and higher resistance to compare.