Eventually printed 15mm 60tooth pulley for prop shaft, and 9mm 120 tooth pulley for intermediate shaft.  My printer is limited to 130 tooth size at 5mm pitch in a single piece.  If I wish to go with larger pulleys in the future they will have to be screwed together.

These can take 4-5 hours to print at only 12% infill.   It would be great to use a much higher infill or solid pulley for durability, but it would take about a week to print this using solar power (can print only 4-5 hours per day).   This gives a first stage reduction of 20:120 and second stage of 24:60.  The total reduction is 15:1