I'm going to buy a Buzz Pro soon and noticed the batteries offered on ProVapes site are Trustfire 3.7v 750mAh. My question is I've found these batteries at batt companies all over the web rated at 1200mAh for less the price. Some appear to be longer than others. Anyone using the Buzz please let me know the length of your batteries. Also which charger would be best? Many thanks, I'm so looking forward to this.