Pics of my maxx

[Serum]

No, it's simple done by flipping the transmission, since the singlespeed uses the same output shaft as the stock two speed gearbox you can simple turn it around. (you can do this too, it doesn't require other shafts)

You can shift the weight balance with batteries rather easy. If the pack is thin enough to slip below the servo horn you can go any way you like it.