Estimate reading time: 2 minutes
Just a short test.. The digit height is around 6 cm, voltage 400V, current limiting resistor 8kΩ. The needle valve is very very fine, it is possible to increase the pressure in the 10-2 torr scale, much finer than necessary for nixie tube work (tens of torrs)!
The blue blurr around the digit is just a reflection in a shiny steel sheet, I placed it here as the anode, instead of the grid.
It was much brighter in the real, just a camera settings..