RE: Sig Hog Bipe build
I got my SuperTigre 75 and I'm going with a 12x5 or 13x5. Not looking for super killer speed, I don't fly too fast, looking more for hover capability. Chances are may have to go with a 14x5 to hover her.
Prop selection all depends on what you wanna do with the plane. Sport flying for fun, go with the recommended prop for the engine.