Yep - easy-peasy. T-piece in the line (to both gauges), connect to one TB and run the motor. Calibrate both to the same setting by using the adjustment screw (not that they've ever needed it). Watch gauges go up and down in perfect symmetry.
I'm glad it's easy, but not as easy as not having to it in the first place.

Plus you get a digital rev counter on the harmonisor, and a seperate balance and gauge mode oh, and a light.