The nightmare starts
I can see a lot of head scratching
With this one.
I am going to have a stainless plate over the board and try to use the onboard buttons to save space.
No usb charge port either as it's easy enough to change a battery
The 510 connection has been modified the small brass center pin connector has been replaced with a brass collet that can be found on ebay used to hold wheels on r/c airplanes.
This gives a better connection i think.
The bottle is 10ml that alchemist cupboard use nice and soft.
Also i have put a ribbon on the bottle that is normally hidden but if the bottle won't pull out it can be spun around exposing the ribbon to aid releasing the bottle.