The transformers have a common ground shared by the primary and secondary. The coax pigtails connected to the low impedance side of each transformer were, along with the low side of both high impedance windings, were all soldered together. The 1 meter pigtails were connected by N connectors to the tracking generator output and to the input of the spectrum analyzer respectively. So, yes, the grounds were connected in the back to back test.
With regard to seeking the permission of the participants in the email trail; no, I did not.