Guinea you might want to call Marc Gaiger, the potter who designed it, and get his take on the comments above.
The tool looks very similar to the one I saw in the video I initially mentioned. That potter I think made his himself when he, like you, was faced with giving up the wheel because of severe arthritis. Although I don't remember who he was I do remember that he had been a potter for 4-5 decades and they had both a huge shop and gallery and he was producing professionally using his centering and opening tool so he seemed to have figured out how to throw with it without sacrificing quality. Of course I couldn't access the structure of his pots but he had a throwing demonstration that looked liked it spun true.
Good luck with it all. I know you love pottery but I would really figure out something so you are not just sucking it up and just going for it, injuring your hands in the process.
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