Here is my take on the variable spacing plate cell:
He has some information on this cell in at least one of his earlier patents too.
It was a demonstration cell
It was demonstrating the "Electrical Polarization Process"
And It was showing the opposite of electrolysis, in the following ways:
By adjusting spacing: you change the electric field strength which is measured in volts/meter, so by reducing the distance, you increase the electric field strength, which shows it is actually voltage doing the work. If you were to change the plate spacing in an electrolysis cell it would do anything at all, because it is amp dependent, not voltage dependent.
This proves it is working like a capacitor, with the voltage fields.
You have to realize that this is an extremely important thing to prove and demonstrate! When everyone around him thinks ... oh he's just doing electrolysis, and then you can vary the gas production by adjusting the spacing alone, it proves it's not electrolysis!
This also varies the capacitance, so I might wonder if you had a variable frequency, and fixed inductance, you might be able to find resonance with this cell by adjusting the capacitance, but maybe you could not maintain electrical resonance to any useful degree? you might just be able to bump into it as you adjust the spacing or frequency. Don says it wasn't a resonant cell, but I still wonder if this was able to resonate just a little bit, which maybe helped him along in his path to the real resonant cell with the phase lock loop.
I have read somewhere, that I can't quite remember where, that this cell was supposedly creating thousands of volts, but after learning about the chokes, with only 50-some turns I dono... you would have to hit resonance to get volts like that. In the same article that said this, it said then he turned on the tubular array which produced even more gas.
I think this cell and setup would be extremely useful for demonstration purposes, which is what he used it for. But it wont produce enough gas to save the world, it might not even give more hydrogen per watt than normal electrolysis, BUT it proves it's different science!