I came up with that means of optimizing valve/chamber shape (Tuliping. Thx freebeard) ages ago while gas flowing my Alpha Giulietta 2L head.
I miss that car! If I knew then what I know now..!
I'm getting my head around what you have said (and not!

) in the rest of your reply.
We'll chat more on that privately. But we are heading into territory where a picture (and gesturing) is worth a thousand words... (in a trustworthy ear!)
IIRC your compression ratio and AF ratio numbers aren't much different!? Hats off on that!
If I understand things correctly (with almost no research) the pre-chamber is basically about creating a very big 'spark' that lights more AF up faster, at a better crank angle closer to TDC, by setting fire to that separate mixture at a/the 'timing advance' that would otherwise be unworkable?
ie:
IF there was a way to create a VERY large spark (or 4...) one could do away with it..??
Hydrogen:
I NB that the previously discussed copper plating that creates a bit of H, more during/after the main combustion event, does not suffer from that drawback in a pre-chamber!
There are a good number of other possibilities for getting some 'free' H2 or Ozone type radicals out of an engine.
eg: A constant but separate (dioded) Ozone producing voltage (circuit) on the spark plug.
I'll get back to you on that when more of my vast multitude of ducks are in a row!

(I'm researching senescent cell clearance for my Mom (urgent) too atm, which is taking a lot of my free time)