MoonBeamZ, are you still looking into getting an Ingulgence V3? Is so, I tell you how I use mine if it helps.
Oh, first let me say that I have read that using the wrong atty/carto resistance can "Pop" the protection circuit in protected batteries if to much power is drawn at once!
Ok, now back to my way of use - I use my Indugence both at 3.7v with AW IMR High Drain 18650 or a pair of AW LiFePo4 3.2v RCR123's. I have four Smoketec Tanks in rotation, two with 1.5 ohm cartos, and two with 2.5 ohm cartos. At work I enjoy the 6.4v and a tank of RY4 36mg, but change over to 3.7v towards the end of the workday with a tank of French Vanilla 36 mg. At 6.4v I use only 2.5 ohm and at 3.7v I use only 1.5ohm. The other two Tanks are filled with TopVape Black Cherry (1.5 ohm) and Unflavored 36mg nic. I keep a few prefilled Ressurectors and a few Boges, pre-filled as well in a zip-Loc type bag in my lunch box for a change if desired. Some flavors, like Candy Cane, which I love are wonderful at 3.7 but very harse at 6.4, the same for French Vanilla.
If I can answer any questions as to the Indulgence, I will do so happily.