I just did mine, and i did the same thing you did, adjusted until i felt drag then did other side other way.
Then i took car to ice covered parking lot and slammed on brakes to see which way car back end swayed. Lucky for me it stayed pretty straight, so i was happy with adjustment. I also double checked if they grabbed at same time by spinning wheels then seeing if slight pressure locked both back drums up at same time. Perfect.
Glad i did it in winter cause ice covered parking lots are all but gone now.