[Alan Anderson]

1: I think you are describing the situation backwards. A higher torque means greater power applied from the motor. More weight on the wheel will generally give a lower speed because of more rolling resistance, so the assumption is true even though the wording sounds wrong.

2: If your goal is merely to drive straight, the scheme of reducing wheel speeds to match the lowest one should work. You will probably want to make sure you know not to use the artificially lowered speeds as a basis for lowering other wheel speeds further.

3: As long as your wheels do not slip on the floor, you don't have to worry about the difference between wheel rotation speed and travel speed. Given a good tread surface and enough weight, slip should not be an issue.