Thanks for the comments guys, I really appreciate your help!
This will be my first time with the 210 on a track with this much grip. Usually I drive on my DEX210 on dusty clay, sand and medium bite astroturf - that's why the battery is completely in the back. That, and my ESC is so big it doesn't fit anywhere else!
I have an idea though: I could make a lexan sheet with the length of a stick pack. On that I could fit the ESC and a battery stopper. I can then swap this around so the battery is either fitted at the front or the back.
Would this be too extreme a change in weight balance (In other words, am I better off chucking some weight under the servo?) or is it worth a shot?