Here is a scan of the three sizes that are used most in the hobby, Mike. As you surmised, the 2x2 on the left is too tight a fit for chips, but works fine for dollar tokens. The 2 1/2 x 2 1/2 in the center works OK for chips.

The 2 1/2 x 3 1/2 on the right was made up by Howdy Herz and is nice for writing info on the holder or putting stickers on them. Howdy did his later auctions that way, and Dean and Jodie in Oregon sell their chips that way is well. Nice presentation, but you get even fewer chips per page. It has a larger cutout as well that will take baccarat size chips and larger denomination tokens. I believe Howdy will sell the holders to collectors as well.