Thanks for the advice. This is a first article in a series so is already being split up haha.

To answer your questions, there is a negligible voltage produced, if voltage was produced by this effect then we could use it as a free energy device. The two important properties for electrical energy is the current (number of electrons) and the voltage (like a force pushing the electrons).
As for the second question the weak link is usually of the order of nanometers. The max distance would depend on the SC's and the link, I can't give a value but this effect doesn't occur for centimeter distances.

Thanks for the questions.