Nice job on your pencilled setting circles. I was thinking the same thing about perhaps AP providing “stick-on-tape” setting circles as visual aids for their mounts, as an option. That would save production work and materials & stocking for the old fashioned types. However, I suppose the pencil (or inked) marked ones can easily wash off or smudge, after all that hard work.
Easy to make permanent ones – just measure and test print such setting angle strips first, on paper. Later , when they seem to be correct with their ends taped/joined, plastic ones could then be printed with a laser printer, onto “overhead projection cell” material, as a clear acetate glue-on. You might have to print on the sheet’s diagonal, depending on axle cap diameter, to fit – or even as two pieces, 180 degree strips. I would first “reverse” the printing image, so that once it is printed (mirror imaged) and flipped over, the lettering would be on the back side of the strip, protected from dew etc.
Might even glue the printed strips onto “Glow in the dark” tape, before applying that tape to the axle. That way, it will be easier to read the angles with the glow backlighting effect, even without a permanent battery operated LED indicator bulb. But don’t forget to account for the tape’s thickness, adding to the diameter, when measuring the printed setting circle strips.