I think you should make it easy and start with a simple project .
The problems you will have are any speed controller will be chopping the power supply and you will not get a steady, easily measured current . There will be a problem with measuring voltage and current - thinking of how you wire it up ( common 0v line ) . Any shunt will limit the motor current in a low voltage hi current circuit and you will need to amplify the signal. All this stuff adds weight- just measure the pack voltage and make do with that ( most controllers include that anyway) .