Dynamic propeller balancing

I’m not doing anything differently. One accelerometer and strobe pointing at a piece of reflective tape on the back of my spinner. I can get it down to .04 ips with a couple washers and slightly longer screws in the spinner attachment screw holes. Quite straightforward. The only other method/tool I can think of to use the helicopter balancer with the second accelerometer but no idea what it would tell you about the gearbox.