About the only thing I'd add is that before you balance a plastic prop (especially an APC) first sand off all the mould flashing from the edges including the tip. I hand start all my engines so I make the trailing edge fairly blunt for about the inner half of each blade. Then check for balance and if one is heavier first remove any manufacturers paint (tip paint, markings). If more is needed then sand evenly all over the front (curved) surface but concentrate more on the outer part of the blade. A little here goes a long way.

With most props you'll find that they'll always come to rest laying horizontally which indicates that the hole doesn't go exactly through the CG of the prop but for general flying this is good enough, it's not necessary to be an obsessive compulsive about balancing