@Joseph Eoff After building and testing these batteries for around 4 months now, I believe there is more going on in them than simple electro-chemical galvanic action to create a standard voltaic pile.  In fact replacing the copper with pyrolytic graphite paper and the zinc with titanium still yields around 1.7V per cell depending on material alignment. That is also using acid-free white paper and distilled water, which are both nearly pH neutral, all to minimize any galvanic reaction. In addition, the same single cell and materials can be arranged/aligned in ways to put out a voltage range from ~.9 - 1.7V, all by simply flipping or rotating material layers. I have never heard of any galvanic pile battery that shows that drastic of a voltage difference by doing the same re-orienting (not re-ordering) of materials. I also have used these batteries to over-charge capacitors and discharge them, multiple times, with a different colored spark than from standard electricity (white hot in the middle).

I don't disagree that  zinc, wet paper (i.e. electrolyte) and copper create a galvanic effect, I just have seen from experimentation that these batteries put out more than the standard electricity we are all familiar with. While the volt meter reads the flow going on, it doesn't mean it's the exact same kind of energy going through it. Nigel has himself explained to me what is going on but it's more than I can articulate here and now. The man has written his own universal relativity theorem centered around magnetism and his understanding of it, which standard physics does not teach, and this battery is a result of him proving out his theories. If you're curious about it I recommend looking up his work on YouTube and LinkedIn, or the videos I put up on Rumble.

Replace the magnets with a clamp.  Same result?  Likely.

These are standard voltaic piles (https://en.wikipedia.org/wiki/Voltaic_pile)

The magnets just hold the stack together.  You could clamp the stack with rubber bands and still get the same effect.  The magnets have nothing to do with the voltage.

Larger diameter disks will give you more current.  More cells stacked together will give you more voltage.

The voltage of the individual cells is determined by the metals used.

Clamping the stack tighter will probably have an effect on the internal resistance of the stack.  the tighter you clamp it, the less resistance there is.  With less resistance, you get more current.  With more current, the voltage will be more stable when loaded.

Your voltmeter counts as a load for such small batteries.  The resistance of the meter will draw enough current that the voltage drops.  With better clamping (bigger magnets) the resistance will go down so the voltage when loaded will be a little higher.