Pin is good the hinge semi unrolled it had a thin spot that allowed it.Did the hinge break or the pin?
I'll still have the old piece if need be. I didn't know it but one of the guys that supplies parts,not Hans,said those breaking is common.The brass is 3/32 of an inch one the old tailpiece. Knowing what I do now, I would have suggested having a shop braze it back together, but what you are planning sounds good. I'll be doing the same thing for a temp tailpiece on the project CE-100.
Brass with platingYou might have the original one brazed, leaving excess material on the outside part not the pin side. Smoothed and polished. But it looks like you are well on the way to fixing it! Are these brass... or? Strange they break....
Save the original pieces.