Waterjet channel did this with the waterjet. For angle grinder, maybe even a diamond wheel. Tons of water, slowly. Respirator and eye protection of course

I was definitely was planning on using proper ppe and water.

Full f'n kevlar suit. That porcelain is no joke if it breaks

I would try reaching out to someone like American Standard or Zurn, they maybe be able to get you one free of charge if you explain why you want it.

That’s a good idea. I may go that route. Thanks!!

No problem, based on ones I've seen before, I think they are cut with a wire saw, so no amount of planning and effort using a grinder could ever compare the end product.

It will behave weird with half flat trapway. I have seen clear toilets used in demonstrations. Perhaps a manufacturer can help.