Drive Train Questions

[Ryank]

The thought for us is to be able to turn with minimal voltage (after assembling the kit of parts into a minimal chassis robot we realized that it drew the battery down to 10-9.5V constant when turning with about 110 pounds on it). We obviously would like to cut that 2.5V hit on every turn to about 1 to .5 volts (or you could think of it in terms of amperage draw, whatever you like, I think that voltage draw also draws enough amps to come pretty close to blowing the 40 Amp breaker). Anyway, sorry to ramble, our idea for drive train, admittedly derived from other very successful robot in the past is the standard six wheel design with two omnis in front and in back and two 2" roughtops in the middle, directly driven by two super shifters with the 48:17 tooth gear set. My question is, will having only the middle two of the six wheels lead to problems? I know that it will cause the robot not to drive straight but we could fix that with a gyro and a little programming right? Or is there a better way to straighten it? We also don't think we'll put any cradle or rocking in the wheels like some, because we have a moderately top heavy robot.