Good Morning Jim,
Thanks for entertaining the idea. Your shared data maybe useful as you have shown same board and relay with different measured results.
For that particular board and the measurement data you gathered, I would say the results ARE encouraging from this viewpoint:
You have 4.5 dBc more margin to FCC spec on your worst case data point (40m 3rd harmonic) with the supplied data set.
I have no measurement error / uncertainty reference or relevant personal judgement / experience to truly offer.
But, I would think it more difficult to accurately measure the case of more suppression, and so the uncertainty here would be higher.
Note that the 2nd and 3rd harmonics are swapping (80m Top and 17m Bot)