I can also attest to your thoughts, that it is the right pv/juice, that makes this a success. There is a personal rhythm to it. I lucked out on my first try, with the Riva and LF juice. Quit smoking the day they came in, (could have knocked me over with a feather! I was shocked!!), But then I had some family members, wanting to share my set, and that's when I started craving ciggs. I didn't have a charged pv, always at the ready, and it threw off that certain pattern I needed. Then juice got low, atties failed...
I struggled, got some help here, (ECF ROCKS LIKE THAT!!!), and righted myself again. It's a process. Expect to struggle at times, but hang with it. It's worth it!