I have seen and heard references to mounting unbalanced props in a certain orientation to help with balancing the piston/rod. Most crankshaft counterweights really are not big enough. I'm guessing you would put the heavy side of the prop in line with the crankshaft counterweight, but that may not be so. I balance my props and mount them horizontally against compression like ChuckW suggests. That makes it easiest to hand flip start the engine too.
ChuckS