Use this for deck wells, not just a number
The useful result is clearance: space for fingers, sleeves, and normal variation. A stack that exactly matches a cavity is difficult to remove and often becomes taller with use.
Method and assumptions
Card count 횞 card thickness, plus sleeve material on each selected side, less optional compression and plus the clearance you choose.
Example
For a 180-card, double-sleeved deck, compare the result with a mocked-up stack and set the well depth above the estimated stack.
Limits
Thickness varies by stock, finish, humidity, and sleeve brand. This is a planning model.