Help with a Lehner Brushless Supermaxx

Hey there pplz, I had quit my R/C passion for a year because of all my univeristy work and applications that i would have to do in the near future. But now im done with all of it and need your help.

I have a supermaxx'd brushless system and completely forgot about my setup and how to work it.

If i remeber correctly i had a Lehner 18120(maybe 150 ill check) controller and Lehner 1570 engine... running with 12 3300's in series, and 16 3300(untested). Now the Y adapter i made before was actually in parrallel and this made my car slower in 2nd gear which was really strange, so now hopefully im going to get a correct y adapter done for me.

1st question: the receiver pack in the pics(i need a host) is a 4.8 volts 250maH nicad battery. I remeber being told not to use over 5 volts for a reciver pack so i bought this one. Will it work?

2nd: my spur gear pinion are 17/72. Is this fine? Keep in mind i have the supermaxx differentials which change the gearing.

3rd: is there anything i should change if i want to use 16 cells instead of 12? i never had time to test the car with 16 cells beacuse of my y-adapter problem.

Please help me, not many people know about brushless in london!