I think it's a great idea because it sometimes takes me a while to get the correct tolerence I wan't at times. Maybe there should also be one of these or maybe just type in the percentage and have these arrows.
This was a very discriptive tut. I'd give this a 10/10.
Here is mine:
I was going to add the alchemy thing either on the background for the floor or the bottom of the inside of the orb.(The white place where your object rests.