many years ago, when electronic runers were fairly new, I spoke with Brian Bowers, who tunes maybe 150 strings before a concert (4-6 autoharps) he said then that he couldn't use them, because (like John in Kansas alludes to above), they weren't perfect...that is, 'G' in one key won't be the same as 'G' in another key, and even on the same 'harp, he wanted the lower notes VERY slightly sharp, and the high notes VERY slightly flat....so he wouldn't use a tuner.

But, it stuck me years later...all he had to do was tune the way he ususally did, then calibrate! Note where on the tuner the note he LIKES is...then mark it! the gadget will give you what you want, if you are clever.