This is not how textual criticism is done.
Famed textual critic Bruce M. Metzger wrote, "Four endings of the Gospel according to Mark are current in the manuscripts" (A Textual Commentary on the Greek New Testament, 2nd ed., p. 102. I have said there are only three, but that is because Metzger's fourth ending is simply the longer ending of the Byzantine textform with a few words added, and it is only extant in one ms, the Washingtonianus, and no textual critic accepts it as being the one in the autographs.
The leading book on this subject is Perspectives on the Ending of Mark, with chapters by such leading textual critics as David Alan Black, Darrell Bock, Keith Elliott, Maurice Robinson, and Daniel Wallace. This is the book of a 2005 symposium on the subject at Southeastern BTS. My son attended the symposium, and after that went to Southeastern for his PhD where he was mentored by David Alan Black, one of the authors. Then while there he was mentored in Byzantine priority by Dr. Maurice Robinson. At any rate, at the symposium there were only two endings discussed: the longer ending and the ending stopping at v. 8. I believe that book would be very helpful to you if you really want to understand the issues.
You appear to be mixing up "readings" with "witnesses." A reading is a textual variant, whereas a witness is a passage in a ms. that has that reading.