I feel the ballast weight merely balances the car out perfectly. If you run your speedo in front of the shock tower you might want to consider adding a small amount of weight up front to balance it out, but it all depends on how hefty the ESC is. I prefer my ESC's on the left side right next to the battery (running wires between the ESC and raised section), receivers all the way out to the right with the ballast weight and I run Venom shorties with a single foam up front.

Regardless of type of track, what you are looking for is balance. Get that right and your car will handle on any surface just the same, with minor adjustments here and there to get it really dialed in.