Matt / Barry- I am just quoting the Lew bible. Andrew asked for a reference from a book, so I pulled up the list in his tome. Like with anything, especially here on Net 54, you could argue the merits of anything, like for example including the Barger Partial B or the Collins Open Mouth as a SP....
For a basic set (one of every player- not the variations) I think Lew's tiering a list is pretty good.
Andrew- on the Joss....I don't know if it is a super short print, but you sure don't see them come up for auction very often. I will say, when I started collecting t205s many years ago most of these SPs were pretty scare on eBay. Today many of them appear each week. The Joss is much scarcer.
Here is mine: