Just did the mailing label thing with the nut on my Guild. Luthier had cut it just a tad too low. I had read this thread a while back and found some labels. String change tonight. Nut off, label in, nut on, buzz free.
While I had the nut off, I sanded the top down so that the strings weren't buried in the slot like Luthier had it done and carefully widened the slots a hair and smoothed them out. Some were pretty jagged. Good grief. $40 for this.
Joy = well set up nut.
Thanks Frank for the tip and others for bringing it up here.