Have to say I`m more old school. Apart from a steel rule which I use as a perfect straight edge to line it up I just use my eye for the string height. Ok, sometimes the strings are a little high but a file soon sorts that out ;)
I can imagine all those old boys 100+ years ago using steel rules and feeler guages and micrometers!
A box, a stick and some strings! No rules!
Oh and of course now we live in the new roaring twenties it`s ok to add electrics ;)
Taffy is quite correct though, always measure twice and probably once more just to be on the safe side.
Look forward to see the photos!