Well, here is the J-Card size: If you want to use a U-Card, you can get more info on the card, but it all depends on how you want to use the J-Card/U-Card.
+----------------------------+
| | --> Back of spine (.5 -in)
+-=-=-=-=-=-=-=-=-=-+
| | --> Spine (.4375 -in)
+-=-=-=-=-=-=-=-=-=-+
| |
| | --> Cover (2.0625 -in )
| |
| |
| <---- 2.875 ----> |
+----------------------------+
For a grand total of 3-inches. From top to bottom.
Enjoy,
Wayne