It takes the same amount of energy to accelerate the
vehicle no matter which end you put the the light wheels
on. That isn't where the location of the light wheel
makes a difference.
Reducing the rotating inertia on the drive wheels will
give you added control if you break traction. A heavier
wheel will add to the flywheel effect on the spinning
tire. To regain traction, you first have to slow the
spinning wheel/tire assy. It will take longer to slow
down the combo that has a higher rotating inertia.
If the car is under-powered and doesn't have a traction
problem, the light wheels might be used to improve the
brake bias. Use them on the end that is being
Admittedly the difference and ensuing advantage might be
small. But a few clock ticks can occasionally make a