Believe it or not, it's not that difficult. Put the tuning peg on as it is, then trace around the washer. Pick out a forstner the same diameter as the washer. Remember that it'll fall just inside the outline. Line it up on the drill press with it stopped, clamp the piece, re-check the alignment in case it wiggled - even 1/16" will throw it off - then drill the hole. Check the depth with the washer before you un-clamp it.
Honestly, it's a matter of eyeballing it with a SOLID point of reference and triple checking before drilling.