I was only using the touching plates as a starting point for a general analysis of what might be happening when you have two isolated, floating, generators linked via a variable impedence. It is often useful in cct analysis to consider what happens under various limit situations. I still use this as one limit, when the potential of the plates would be common and the generator voltage levels relative to the plates, and each other, would be variable. The other limit is an infinite impedence, also not achievable, when both generators would operate independant of each other. We are considering an in between situation where currents must flow between areas of different potential, but these currents are not part of the normal operational current, as this must flow back through its own plate. I suggest these currents are capacative and cycle back and forth between the two circuits.
I am not an expert, I am only offering a way of thinking about a complex electrical problem, in the same way that you might use the water analogy (pressure, flow, and restriction) to think about Ohms Law (voltage, current and resistance)
