Everyone seem to think it is best to position your prop so as to avoid a prop strike during a gear up landing. I've thought about this a lot and it seems to me the only hope you have of not having a prop strike by positioning the prop is with a two blade prop. I don't think there is any sweet spot with a three blade? I also think a crankshaft has a better chance of survival if the prop is spinning when any of the blades hit the ground. The impact on a two blade is once very 180 degrees and a three blade is once every 120 degrees. The nose is coming down at a given rate no matter which blade you are running so a two blade is inherently going to be more damaging than if it were a three blade. I would think if the impact was entirely against one blade, if the engine was stopped and blade down, a bent crankshaft would be more likely. Likewise, if the prop is spinning, torsional damage is less likely with a three blade over a two blade as impact load per blade is less than a two blade.
Does this make sense?