Posted By:
jay woltI agree w/ Mark's assesment.
The action cards like Safe At Third, Out At Third, Jordan & Herzog, Close Play at Second, Trying To Catch Him Napping, Jack Murray At Bat & Chief Myers At Bat do bring a premium since less are out there.
Other horizontal shots may bring a premium as well albeit a smaller one
like Boss Schmidt & E. Lennox.
There are 5 different backs in the set.
The only one that brings (& deserves) a premium is the very tough
checklist back w/ no ordering information. I have 115 diff T3 & T9's
but only 3 w/ that back.
The ad backs are only issued in the high # series (#77-126) so in essence
they are a bit tougher then the checklist back overall. But as far as the
high series goes many of the players are easier in ad back like Walter
Johnson and some are much tougher in checklist back like Bob Rhodes.
I will pay no premium for a card I need w/ an ad back, and almost half
of all the high #'s I have are ad backs.
Here are a couple of action cards that I just landed this week.
#43 Out At Third 
#45 Jordan & Herzog 