[Topnotchsy]

My $.02.

• It is likely you would get the most value breaking them up.
• I do not believe the auction houses would necessarily guide you right on this. For them, breaking it up means additional auction listings, and the value might not be there to really warrant that in their eyes. (Consider that an extra $1000 in your pocket is worth maybe an extra $200 in their pocket and so the incentives don't perfectly align)
• To some degree it depends who is on a page together to determine the value and how easy the signatures are to separate.
• The bigger names (Mantle, Maris, Ott Speaker and possibly Stengel andDean) are most likely worth the money to authenticate. Many of the names, (Larry Doby, Minnie Miñoso, Early Wynn, Brooks Robinson, Phil Rizzuto, George Kell, Rocky Colavito x2, Bob Lemon, Jim Bunning, Whitey Ford, Yogi Berra) despite being great players, don't carry enormous value. So those may be worth selling in a lot/collection without spending on authentication
• There are differing views (as this thread shows) about cutting up items. I'm in the camp that does not see an issue cutting up an arbitrary item like this, but would not do so to items that have more historical significance as a whole. I have a Jackie Robinson college yearbook signed 4x which I could likely make way more money on separate than together if I chose to sell, but can't see myself separating the pages... so my line is somewhere between what you have and what I have.

Cool item, good luck with it!