The original Provari was actually mechanically designed around an AW button top battery. Probably the main reason why Provape was so intent that customers use AW. The design's intent was to prevent reverse polarity (putting a battery in upside down resulting in frying the circuit board). Flat top batteries couldn't make the electrical connection correctly no matter which way they were put in.
I guess some of the wider button top batteries may not fit appropriately, but most should. Not so much because of the length of the battery, but the button top must match up correctly in width with the positive battery connector inside the Provari. The positive battery contact you see below in the Provari's circuit board has two elevated pieces opposing one another (at 6 and 12 oclock) that the battery button top must fit into to make electrical contact.
Excellent! btw- early 2018, LG HG2 is indeed in button top, avail. Authentic OEM from your fave trusted sellers such as
RTDVapor
LG 18650 HG2 3000mAh 20a Button Top
They offer guarantee against counterfeits..
Any ideas on the button top safe guards built into the ZNA? No, I wouldn't dream of noodling around inside mine,
Presently we've a plethora of BT choices available. (30Q, NCR18650B, HG-2 BT, ).
For 18650s remember to double check measurements as they’ll vary between 65.12mm -69.4mm length, even when
Width is close enough to 18 to be serviceable, you’ll need to be certain your batts will fit in your PV before you order
Since returns on batts may be limited (you might want to check those terms too).