I do plan to reccomend the LRP 21.5 slave and the Meanwell Power supply. Errors in the Power estimate with this motor and the Meanwell power supply should be low. The spreadsheet can be setup at the bottom of the page to allow data from different slave motos to be entered. The formula will be self generating. For better accuracy a flywheel run could be used. Repeatability with the flywheel is within a couple of percent on three runs. Repeatability with the slave will be determined.
I have my power supply and slave in hand now. I will be able to do a run in a few days.
The theory behind using a flywheel and a slave is to have the motor undergo chassis rotational inertia drag and then follow up with a change to aero and friction drag.
john