24. Bates (Print Group 1)
Here is a fun one. The PSA pop report does not include an entry for the SC 350/25 of this card, yet there were 2 cards that are labeled as 350/25, and I found a total of 5 of the 350/25s in PSA holders (the other 3 were in Sweet Caporal or T206 slabs)
We've now looked at 2 subjects (Alperman and Bates) that have the 649OP back, and I think the spread between the 5 SC factories is pretty interesting