For the Saito .71 try a 13x6 or 13x4W APC prop. The 14x4W will be too big and heavy for quick acceleration, which is just as important in 3D as power is. The 13x4W might rev a little too high and might not give you the overall performance you are looking for. I think you end up going back to the 13x6 everytme...

For the Webra .50, try the 11.5x4, 12x4, or 12.25.3.75...