To answer the LVC question, the ESC automatically detects 9.6v (7cell) and if the LVC was set at 3.0 it would not take long for the nimh pack to fall below the lvc threshold.
Hope I was clear on that lol
Glad you got everything working and now need some running video
. If you want to see dramatic performance increase pick up a couple 2s lipos and you and your son will get much longer run times.
Glad I could help and if anything else comes don't hesitate to ask.