Whew, Peter, that DMT was a stroke of genius.
This is going to be a sweet little tool when you get all the features set and the details ironed out.
Nice job!
Oh, yeah- the range holes do work. You view an object through a hole using a set length of cord held to the end of your nose and you extend the tool away from you to the end of the cord and view the object through a hole it just fits into.
The holes are supposed to be calibrated to a fixed size object (say 5 feet tall) at different distances, always viewed with the cord extended fully and touching the end of your nose.