Basically from what i understand 24 tooth pulley / OD 37.08 at the lower point at the tooth/ can not be fit, had to be machined on the shaft directly? So the next in line is the 26 tooth pulley which is OD 40.24 at the lower tooth point, so that will give 40-35=5/2=2.5mm wall, which seems quite thin. Then 28 tooth pulley is 43.42-35=8.42/2=4.21.

So it seems if not machined directly, the minimum pulley will be 28 tooth? Or am i missing something?