Thanks for confirming they are the same. That's the general idea I got from reading, but there's so much misinformation out there on the internet and wasn't 100% sure.
What you're saying about the special friction plate makes sense. When looking at yoyodyne and sigma's instructions, they do not mention making sure you get a different type of friction plate however. I assume this is because wear isn't too excessive. Did they recommend that you don't use a standard friction plate?
I understand why the judder seat and spring need to be moved, so they can't get jammed under the hub when it lifts.
Disc A is the one with the larger inner diameter so the judder seat and spring fit inside of it. Disc B is the one with the special friction material. I assume the special disc's you're referring to are two disc b's?
So is this correct? or... ? I think you have 1 too many plates in your example and don't have disc a matched up with the judder seat+spring.
(from inner to outer)
disc b / steel / disc a with judder seat+spring / steel / normal / steel / normal / steel / normal / steel / normal / steel / disc b
Not sure if I have it right, just trying to learn before I place my order.