Just had a nice chat with Crazysinnester on the phone and he let me know that while the Lemon Drop Glass size does work on the Salamander you cannot use the metal windowed sleeve with it. The inside of the sleeve is 21mm and there is no Borosilicate (PYREX) size for that. There is a 21 x 1.5mm Fused Quartz but we do not currently stock that size and I would question as to if it would even work since glass has to have room for tolerance the ID of the metal part would have to be at least 21.4mm to allow for differences in the tubing. EDIT*** Crazysinnester, Just realized that would have to be 21 x 1mm, dunno why I was thinking 18mm ID and from what I can see there is no glass that size.
All glass has drift as it is made by drawing or pulling from molten glass, computers control this by constantly pushing towards the nominal size so if it is running large it corrects down in size or up if it is running small. Good glass from top brands as in the Simax we use is amazing close considering the manufacturing of this stuff, Chinese glass has historically been all over the place on size. For device makers we are happy to provide specifications of tolerance for different sizes if they request it, if I were designing a device in this size range I would use 22 x 1.8mm glass as it has the tightest tolerance +/- 0.30mm on the OD and +/- 0.10mm for the Wall. The 22 x 1.2mm has the same specs but the added strength of the thicker wall is worth the small tradeoff in eLiquid capacity.
One thing Crazysinnester brought up and I wholly agree with is using glass rather than plastic. In his case it is for more caustic eLiquids that show quite visible effects on plastic tanks. For me vaping mild eLiquids I dont care to chance the possibility that any amount of plastic might be leaching into my vapor whether I can see actual damage or not. This is the reason we quickly went to glass three years ago and have only used it since.