Echoing what Seabee says. After sharpening, weigh them but you have to do better than your bathroom scale. Aim for 0.1 lbs. If you really want to do the best job possible you can first measure the length from the center of the mounting hole to the outer edge. Make them equal to within 1/64th inch. Do the same for the mounting hole to the short inner edge. After that go ahead and weigh them. If you need to remove mass take it equally along the length of the heavy blade's non-sharp side. This way you have done your best to match both the geometry and the mass resulting in the same moment balance.