A customer of mine by the name of Bob recently requested a new rapier blade. He had an interesting formula for comparing blades. He simply divided the distance from the tang end to the balance point by the distance from the tip to the balance point of the bare blade. TangToBalance/TipToBalance. This gives a dimensionless ratio which is generally less than 1.00 and useful for comparing two blades of approximately the same length. I call it Bob's Balance Ratio in his honor. Of course it doesn't take into account the weight of the blade. I suppose you could multiply this BBR times the weight of the blade to give a rough estimate of the angular momentum. A number of years ago a guy on one of the sword forums was using a similar formula to compare complete weapons. He called it the Feel In Hand.