For a slow flying model... I will often put a 12.25X3.75 APC or a 12X4 Zinger wood prop on a .46.

When vertical performance is desired that is also what I will use on a .46.

You get high static thrust and the ability to take a suprisingly heavy model unlimited vertical. The low pitch also helps contrl speed in vertical descent, and allows you to slow down easilly for smooth landings. (the plane might slow down better with the engine running than with the prop stopped!)

10X7 or 11X6 for most sport aerobatic types which are light enough to get adequate vertical from the prop.

9X8 sometimes when speed is the goal... and I have plenty of runway. (and only with a lightly built plane that is made for speed...)

Match the prop to the airplane and the engine as wellas the way you intend to fly it... the plane will perform better.