The 720 motor is usually faster but has less torque than the 820. That means with a larger prop the 820 will do better. The 820 motor has a larger stator, providing higher torque but slightly lower RPM. At higher voltages, both motors spin significantly faster. HOWEVER, not all of them can survive 2S power.
Overall, the 820 motor is slightly larger and heavier but tends to last longer due to better heat dissipation.
60mm prop seems to be the most optimal for 720 coreless motor.
72mm prop is still ok but you must have a very good 1S battery to support this.
820 motor can handle larger prop easier.
The problem is that a larger prop may not always be good for the motor. A larger prop is usually thicker and therefore heavier, thus increasing the workload of the electronics and the motors significantly, often resulting in slower RPM and therefore less thrust.
In the following Fighter Glider configuration, the smaller props actually do much better – instead of increasing the prop size we actually extended the elevator, which ended up allowing the glider to get into the air flawessly.
The same trick of extending the elevator may not work with the Lido style glider. Based on our test results, the Lido glider does not benefit from it at all:
This glider has 2 x 720 motors using 70mm prop.
