Tops can be graduated from the top side or the bottom. It's just harder to check the thickness with the mandolin intact. Keep in mind you may need to...
Great job on building the case Steve. I've always wondered why there wasn't more of build your own case movement. Some people build some heavy boxes....
There are individual mini tuners used mostly for guitars, just make sure you get the right orientation. They are usually sold in sets of 6, 3 on each...