I watched a video the other night on setting Z-offest. I didn’t agree with everything this kid had to say but he did have a good idea for tweaking the Z-offset while printing. He had a large square he printed that didn’t have any outer walls so basically he was just printing the infill. You could download the gcode from him but I thought it would be easier to make my own, which I did. Anyway the concept it that it’s big enough that you can see and feel what’s going on then make minor changes to the Z-offest and watch it print some more fine tuning as it goes. Seems like it would work pretty good though I haven’t tried it yet. The square I made was 70mm x 70mm
That is, more or less, what I have been doing for months. I always fine-tune Z Offset by printing 1-layer squares. Mine are only 20mmX20mm, and they do have outer walls, but it’s the infill solidity and smoothness I’m looking at. And I do fine tune the Z Offset while it’s printing. Often, I can get 3 Z Offset settings in 1 square. I look for the point where I can’t break the joints between infill lines, the surface is smooth, not rough, and it’s as shiny as possible. I did 50mmX50mm squares for a while, but found I didn’t really need them that big. That said, I may go to 25mmX25mm or even 30mmX30mm.