re: Show the restoration before and after.

My sample size is only 1, but the one I have does not have any graduations.  The bubble is not a whole lot bigger than the "window" on the side, though, You're also manually setting the bubble level to a degree based off a 1/32" wide pointer on a 2" dial, so anything beyond "close enough" is probably outside the scope of that tools usefulness anyway, I would imagine.  

I'll check my 12" vial, once it gets here 😉