Common Practices and/or Guidelines
1.  Gearing selection on the other sheets are a starting point.
2.  The gearing may need to be modified if running conditions place more or less strain on the transmission and differential.
3.  When running in sand with off-road wheels/tires, gearing down from the sweet spot is likely needed because it causes more strain on the tranny.
4.  When running on asphalt or pavement or hard-packed dirt, gearing up from the sweet spot is likely needed because there is less strain on the tranny.
5.  Motors with lower turns may need to be geared down to reduce heat build-up.
6.  Motors with higher turns may need to be geared up to reduce heat build-up.
7.  The lower the turns a motor has, the more top end speed and and less torque it has.
8.  The higher the turns a motor has, the more torque and less top end speed it has. 
9.  The more number of winds a motor has, the more energy it takes to get the motor to spin at max RPMs.
10.  The fewer number of winds a motor has, the less energy it takes to get the motor to spin at max RPMs.
11.  Wheels with a larger diameter will require a smaller pinion as it takes more torque to get them spinning at max RPMs.
12.  Wheels with a smaller diameter will require a larger (taller) pinion as it takes less torque to get them spinning at max RPMs.
13.  Smaller pinions increase torque and decrease top end speed.
14.  Larger (taller) pinions increase top end speed and decrease torque.