Several things to comment on here. First, there was an actual one (1) blade prop in the old days for a full scale aircraft. The opposite side of the hub had a counterweight to maintain balance. It was too inefficient and discontinued. Many high wing turbine aircraft such as the Dehaviland DHC-6 I used to fly use 3 blade props and ground clearance was not an issue, fuselage clearance was. Several different blade shapes have been used on multi-blade propellers. One of the critical items is to keep the blade tips from going supersonic as they turn. The tips of shorter blades are traveling slower at the same RPM as a long blade. This is also a limiting factor in full scale helicopter flight. By using more, and wider, blades the necessary thrust can be obtained. Also, as far as blade angle is concerned, remember that all advanced aircraft are going to have variable pitch blades (for a multitude of reasons beyond this forum discussion). Aerobatic full scale aircraft such as the Pitts series use shorter composite 3-blade props to reduce blade weight and flexure as this can actually (and has) break crankshafts during the violent manuevering. For a model, get a prop with enough ground clearance and experiment for the best pitch for your plane. Bye.
Bruce