Not sure how many people will read this post but here goes...
Just how accurate does fret placement need to be for there to be a perceptible difference to the accuracy of a note to the human ear?
I'm looking at using a cnc router to mark the fret positions. When using mm scale it rounds the 3 decimal value of the fret position calculator to 1 decimal place. If you change to imperial it gives 3 decimals, and 0.001inch is less than 0.1mm. Do you think I should use the imperial scale or 0.1mm is accurate enough? This is assuming there isn't major inaccuracies to the mechanical precision of the router.