Here’s a table of sorts for Jigs and the max distances they can be read from.
Also, just in case anybody has a 3D printer/CAD , the jigs can be printed out. You need a dual extruder though or another method of switching filaments while printing. We’ve printed them as small as 1/4" though they can’t be read from a large distance (table above should help). If the “data” part of the jig is printed on the build plate then it leaves a nice matte finish which isn’t as susceptible to light fluctuations.
Hopefully this is useful to at least some people.