I have runners knee & am wondering if there's an effective but minimal brace to wear both knees when running that helps w/ knee tracking?

Yes and no: There is a fairly minimal knee brace known as a patellar sleeve that can potentially help if your symptoms are related to patellar maltracking. One of the more common causes of knee pain is called TFL syndrome, related to a tendon that runs down the lateral thigh and inserts on the lateral knee, and braces don't help too much with that, but taping and stretching can.