I made a test run today with two different props, and wanted to share the experience.
It is a 5 inch copter with two types of props:
three blade 3 x 5 x 3.7 APC and
two bladed 2 x 5.25 x 8 APC.
I tested the two configurations in hover and slow flight, one where similar props on one side (i.e. 5.25 x 8 were at the rear, and the other at the front), and another configuration with same props placed diagonally.
The result: copter flew very well in both configurations. The first configuration with two motors at the rear and two motors at the front had a slight issue when accelerating hard in hover, it would tilt forward somewhat, maybe by 5 degrees, but then recovered immediately. With diagonally placed props, virtually no palpable difference could be felt compared to standard prop configuration.
The reason I am doing this is to test out the possibility of making a high speed VTOL with two retractble motors. High pitch motors would be fixed on the wing, low pitch motors would be on retractble arms.