Did I see stirring going on in there or are you allowing the water to agitate by convection?

No, there is no stirring, but just natural convection provided by the hot waterbath in the bottom.

I still haven't tried adding a very fine cathode in the centre of the Anode array, though I get the feeling it could improve the propagation of ion donation as and wearability even further.

That being said, what are the sizes(dia.) between your anode and cathode?

I am testing this array with 1 cathode (center) and 4 anodes. The distance between the cathode and every anode is 30 mm.

For the batch shown in the ideo I was using:

• Cathode: one silver wire gauge 10, new, 15 cm long
• Anode: four silver wires, all 15 cm long. Two of them gauge 10, new. Two gauge 14, old.

My finding so far...

• Seems that the cathode is overloaded. The voltage droped very quickly and the cathode became black; I had to clean the cathode around 10 times for the batch production. This setup shown in the video has improved security and hardly will allow any confusion between cathode and anode, so I am considering use as cathode a large diameter inox still wire or other metal that less sensitive to oxidization.
• As happend in the previous batch using this setup (but with 3+1 wires, instead 4+1, like now), the voltage droped until around 5.8 volts, hardly going below. This possibly is due the black oxidization around the cathode that acts as a kind of isolation; by cleaning it the voltage droped to 5.2 volts, but rised back to 5.8 with the reoxidization of the cathode.
•  For tis particular setup in this video the current of 5 mA seems too low. To be able to finish this particular batch I had to rise the current to up to 15 mA at the end of the production process.

As the the next step would be to adjust your current to bring your process, cathode build-up and voltage drop together. That is to say that all three control points will come together at the same time. ie, your voltage has hit 9v, your electrodes are in need of cleaning and you've moved sufficient silver into the solution to complete the task with as little change-out as possible(efficiency).

Seek that balance seems a good strategy and will provide convenience.

I am also interested in produce with the highest possible ionic content as it is (believed to be) an important CS component for the healing process.

One tip that may prove useful is to allow your cell to heat up to the point where there's no longer any bubbles on the electrodes. This serves as a good benchmark for maximal temp and water conditioning prior to processing.

Heat up is a good tip to reduce the water hability to retain air in gas format (adsorbed air), but I guess that most of the buble we can see in the video and are around the silver wires are Hydrogen and Oxygen resulting of brake of the water molecule (H2O) by the electrolysis process.

can the external bath withstand the boiling water temps?

Are you talking about the dark blue plastic container?
Yes, it withstand easily to the boiling water.

Some people are surprised, but it is possible take a plastic bag, fill with water and boil the water by placing the bag over direct fire. Just have to take care to avoid the flame to hit the parts of the plastic that are not in direct contact with the water.