The way I figured it out, with my Kontronik 700-45 was use the 14or 15T pinion for the E6, then just use either the 12 or 13T pinion for running the E7.... If I recall, the difference in HS, is perfect for 600 sized with the larger pinion, and perfect for 700 sized for the smaller pinion....
Somehow I think Matt did this on purpose....
Oh yeah... and these would both be 12s setups.... Currently I use a set of TP 4400 mAh batteries and the fit perfect....
Good luck,
Joe_Breezy