I gotta say I really enjoyed it. Very original, very clever, and pretty difficult too.
I think my base could manage 25spm if I grouped up my main cyclotrons so they shared the cube instead of having multiple train stops due to not realizing I would need multiple of them. My antimatter production area is also probably way bigger than it should be, but I'm honestly not sure how to deal with that.

There's only one problem I couldn't completely solve: sap. Factorio fluids are ever so slightly lossy due to floating point rounding errors, so it's impossible to be 100% efficient with sap delivery and I don't think it's safe to automate producing extra (well, maybe with some complicated circuits to precisely move things between belts) so I manually diverted the resource flow for one cycle in my antimatter setup to generate a surplus, which is very very slowly going down.