It works fine on my '68 D-18, my Brook Tavy and my Tanglewood parlour. My Alvarez guitars all have built in tuners.

The trick I find is to locate the PW micro between the 1st string tuner and the nut with the display underneath the headstock and angled toward you. No interference with the decal and even my podgy hands don't get in the way when tuning. The display is small, but as long as I wear my glasses ...

Comment invited.

Alan