A chain sharpening rig for a rook..

That Granberg style file guide has a backstop on it so as you bring each tooth through you back up slightly to the sharpening position before you run the file across the chain. If you do that consistently you will "normalise" it yourself every time you touch up the chain.
What I do is set up then adjust to just barely touch the tooth with the file. Then I adjust the depth setting a bit deeper to actually remove some metal. Since the adjustment doesn't move during the sharpening process all teeth end up the same exact depth with no extra effort from me. Look at your file-n-joint when it is mounted. The thing, what I called a backstop, is a screw mounted behind the file that a flat metal piece runs on as you move the file across the chain. If you manage to rock a chain you can even get set up on the worst tooth and then get them all filed to that length to restore a chain. Instead of 2 or 3 strokes for each tooth it might take 20 to do that.

 

Rocked chain is where a grinder shines. Just go slow as to not heat the tooth too much