The LT-40 was my trainer which saw me through the flight training and solo stage (without a single crash). FWIW, taxiing was the most difficult portion to master. I wound up with lots of time on the simulator.

As far as balancing the LT-40, start with the CG where the instruction booklet tells you to. That will be on the forward side of the main wing spar. We haven't started to wring ours out yet so the throws are set at their minimum as per instructions. I also have a computer radio with exponential on the primary channels (aileron & elevator). My Futaba 6XAS also has expo on rudder. I installed the battery and RX under the fuel tank with the battery pack forward of the RX. I use a ThunderTiger .46 Pro for power. It is a ball bearing engine like your 46 AX. I found the slight additional engine weight balanced my LT-40 perfectly with no additional ballast. I hate carrying dead weight. You'll appreciate the added power of the .46 - especially when coupled with a lower pitch prop like an 11-5.