23 style available at electric dealers. Divide again using one of the gearbox ratios shown at left. This is the drive resolution. You should assure that it is not too large because you will see the step motion. If too small - your slew speed ability for fast pan will be poor.
More torque is available due to the higher gear ratio.
Less torque is available due to the lower gear ratio. We have a 360 tooth worm gear on Ra and a 240 tooth worm gear on Dec. We select R15 gearboxes for both axes. Dec. Torque to the wormshaft would run about 30 OZ-IN for Ra, same for Dec. Changing to an R30 gearbox would halve these step sizes, double the available torque, but halve the potential slew speed. This will give you an idea of the range to expect even if you don't actually know how heavily loaded the motor is going to be.