So i'm about to buy my first tank mod, and I was wondering if there are any benefits of either using a 3ml or 5.5ml (phat version)? I don't think i'll ever smoke 5.5ml of the same liquid so 3ml would be just fine. However, is the 5.5 easier to fill and less likely to leak than the 3ml? I want ease of use and leak proof over anything.