Stuart, I'm fortunate in that I have CorelDraw on my machine, a vector graphics package that I use quite a lot for DTP and publishing. So I use that to make a printable file.
How do I set the marks? Well, I wrap the sidewheel in masking tape, mark the tape with the ranges as found by experiment, then lift the tape off the wheel, stick it to a flat sheet and run it under the scanner. Next job is to create the image as a vector file just by tracing over the marks of the scanned image.
Then print, and stick onto the wheel. The original masking tape strip goes into the dustbin.