I was able to remove the ring, then I ran out of time. The opening measures around 22mm now. I will open up the hole more to fit my knot that is 24mm. I have to ask how far does the shelf go down. I am just past 20mm and I still haven't removed all the shelf.
I don't mean to hi Jack your thread, I just created a new one with the same type 100. How did you remove the cup?