All true... First, thanks to the Beta team for the insane amount of work that they are doing behind the scenes as it has lead to this amazing advancement in the single battery manual unit.
The 14 mm glass is flow restrictive and load limiting. In comparison to the 18 mm it is actually quiet disappointing as compared to the Zion as noted by
@pakalolo attested... You know he has written papers on convection right?
This change will not increase the size of the unit as we recessed the 14 mm and will not recess the 18 mm to make up the 4 mm difference. We have also tested an ultra short stem and due to the heaters cool vapor it isn't hot or harsh, in fact due to the more uniform vaporization / ABV the 18 mm actually is less harsh than the 14 mm.
Part of the signature of RBT is the insane power and wide open flow path and the 14 mm is just to small to satisfy the Mantra of "desktop power in the palm of your hand"
With the generous flow path comes better temperature control such that it is just a matter of how long you hold th button down ... Minimal pulsing and stirring are great attributes of the bigger glass.
Although not tuned to run like the TOD you will be able to buy a TOD kit that will contain a spacer required to run two 18350's nearly doubling the available power... That one is for you HD and any of our customers that want to grip it and rip it TOD style.
This seems like a win/win situation but if any of our pre-orders are not happy with this change of direction we offer a full refund.
If you have been around he RBT threads at all you know that the only guarantee is rapid change so if you jump in on the the pre-order for either of the manual units hold on tight and enjoy the ride.