I have always liked Graupner props. They have a nice wide scale looking blade and just seem to be stump pullers. I have run 2 and 3 blade props on the same aircraft before and I always try and keep the pitch the same but lower the diameter by 1" when switching from 2 to 3 blade prop. Here is the web site for Graupner props:

http://www.hobby-lobby.com/grprop.htm