Bike Gear-Changing System, Torque and Speed

Left Handle Bar gear shifting (TORQUE sprockets attached to pedal):

Low
1 - smallest pedal sprocket - lowest diameter, lowest torque
2 - medium pedal sprocket
3 - largest pedal sprocket - highest diameter, highest torque
High


Right Handle Bar gear shifting (SPEED sprockets attached to rear wheel):

High
7 - smallest rear sprocket (fastest speed)
6
5
4
3
2
1 - largest rear sprocket (slowest speed)
Low


Personal favorite configuration:

Left handle bar gear position :  3 - High Torque
Right handle bar gear position: 7 - High Speed

* In this setting, I accelerate faster, I apply a decent force on the pedal and gain speed faster.