Not that it will help your newest bling, I would have the third set of rims balanced out when you clean up the mold lines, use removal of material as the balance method. My last three sets of tires required no new weights, IOW, the 'Stones were not as balanced as the Stradas, which needed balancing, but the following PR2s, Angel 50s, and 55s needed no new weight shift. Luck?
If you are going to this level of perfection and as it's obvious money isn't the blocking point consider doing a static balance on the rim after removing mold lines, and remove enough material at the heavy side and than mount a new tire, check balance, if good, recoat.
Problem solved.