I've done mine. Nothing fancy just a few improvements here and there.

Massive - it's not almost impossible to balance, it IS impossible to balance. A good medium is to measure the weight of the piston + wrist pin + conrod, then take 55-60% of that and make a weight that you put on the crank pin. With that done you go ahead and balance the crank including the weight. This gives a good dynamically balanced engine.