Recommended voltage for different resistance coil head: (4-8 watt range)
1.8ohm: 3.00V - 3.75V
2.4ohm: 3.00V - 4.50V
2.8ohm: 3.25V - 5.00V
There are instructions on how to fill cartotanks, with step-by-step photos, here.
Many would disapprove, but it has helped curb my cravings. It helped with weight loss before my weight loss surgery and now I mainly vape to keep myself from eating the "wrong" foods.
Early cigarette ads encouraged smoking to lose weight. Here's one example: