RE: Is there any advantage to going with a higher amp ESC than you need
A bigger esc will have less internal resistance (means more gets to the motor) you will get a little more out of the setup.
I use 25-50% more than needed for this reason and also to not heat up the fets in the esc as much, full stick for 3+ minutes at a time.
I have setups that pull 80-90 amps at 25v 6cell and it is very measurable at these voltages and currents, over 2100+ watts.