Not to throw a rock in the gears, but I question the idea that this will be the best selection. In general a larger diameter prop has the potential to operate more efficiently but in most cases the drag of the plane will keep you from reaching the speed necessary for the prop to reach this efficiency level. You have also said you do not fly for speed high pitch props are for speed. A large diameter prop with a lower pitch will generate more thrust at lower speeds and from what you are saying about the way you fly this plane the prop you are currently using or maybe even a prop with less pitch might be the way to go. You might even look at slightly smaller diameter prop with less pitch which might increase the RPM some, you may see a substantial increase in thrust at low speed which could help in getting airborne and recovering from trouble. If you are flying for endurance efficiency might come in to play if your flying for performance you might look at some other options.