I do something similar. Page one is the set of characters I am specifically working on improving right now. I move folks onto and off of page one as needed. After that it's pages divided by AT, subdivided by level, alphabetically. So a couple pages in I have two pages of Corruptors, level 50s at the top, going down, for example, though there may be a skipped slot where I've temporarily moved one to the first page for ease of access on a "current project" character.