[weldtoride]

Welcome to the site. Having done some small scale spinning, I would agree, and rate your spinning goal specs extremely ambitious for a home shop. Have you done any spinning at all on a small scale?

Meanwhile, as an alternate plan, here in the US, "tank heads" are available custom made and also in some stock sizes from a number of different manufacturers. Some are spun, others are drawn. Don't know about your part of the world, but it might be worth a look around your industrial formers there.

"Tank head manufacturers" is a searchable term here (substitute "end" for head as well) with loads of results, but maybe they call them something else in your neck of the woods. Lots of our suppliers are near oil and gas processors, and also near ship building yards. At least a visit would show you how big a lathe you would need.

Good luck with your endeavor, sounds like you have a great start on a shop.