Adrian,
Battery position is usually dictated by the motor. A mod. motor usually needs the batteries further back then a stock motor. The further back the batteries are with a stock motor the more rear bite and less responsive the stearing. I would run the car almost full throttle on any layout I ran on with a stock motor with the batteries very close to all the way forward. Maybe if you are on and off the throttle in stock it may be easier to drive with the batteries back some. In mod. I had to run the batteries back further to gain initial take off traction, then get the "pendelum" affect as the car went threw the turns to gain stearing. I would also have to run a thinner t-bar in mod. which does the same thing. The mod. motor carries so much more entry speed that the thinner t-bar let the weight transfer quicker and get you threw the turn faster.
Wayne
