Done a bunch of maths and scripting to revise this mesh design to optimise it.
It'll feature a rectangular panel to display 3 digits at once using a texture that has numbers from 0-999. There will be three of these digit panels each with a separate material.
Between the digit panels will be locations for separators such as commas or points.
I also want to be able to support negative numbers. After a lot of thought, the best way to approach this would be to slide a minus character left/right depending on how many digits the number has visible. So there would have to be a long thin rectangle going through all digit panels as well as extending out so that I can place the minus when the display has all 9 digits occupied.
In terms of relative sizes to reference for the geometry (via pixels in the font texture):