Interesting that you note the extra coil to be 1/2 wavelength long vs 1/4 wavelength. I guess together that would produce a 3/4 wavelength system that would still have a voltage maximum at the top. In Richard Hull's Guide to the CO Springs Notebook, he states the primary and secondary can be a huge range....the important thing he notes is that the primary secondary can be highly coupled and acts as a high power signal generator. He feeds his primary and secondary into a 1/4 wavelength coil.

Really excited to see your results following the 1/4 -1/2 wavelength secondary and extra coil. Makes sense. Ive primarily used Richard Hull's advice and gone with a highly coupled primary & secondary to increase power into the system, but perhaps this type of system is missing something.....

Looking forward to the results!