It dawned on me this morning that a "sleeve" of graham crackers is a rather variable term. After all, the brand I use may include more crackers in a sleeve than another brand does. To clarify this measure, I'm going to grind up a sleeve of my graham crackers and update my recipes with more specific volumes.
Update: A sleeve of my brand of graham crackers equals 1 cup of finely ground crumbs. I've updated the recipes accordingly.