Yes, Mauro, that is correct for 38AC's balancing method which I highly recommend as a time saver, and getting the smoothest possible running engine. The two flyweels first have the counterbalance center of mass corrected to the proper location relative to the key, and then have matching counterweight values by adding weights centered on the proper counterbalance location. Fine tuning is then done easily by adding weights at or opposite both counterweight locations. 2 ounce increments seem to work for me. Too little counterweight produces floor shaking, up and down movement. Too much causes fore and aft movement of the cylinder head. One you start to see just a little bit of fore/aft movement, you are in the sweet spot for a smooth running CS. You should be able to sit a cup of water on the cylinder heat cover and have only a little rippling of water. The feel of your feet and eyes on the water and cylinder head movement will be your guide.
Best Wishes,
Bruce