You will find that a lot of the tunes notated come out in the wrong mode. The whistles are tuned in a diatonic major scale(or they are in the crackers I got), so the C to C tunes come out fine. But the ones with keynote F come out with a sharp 4th(B natural instead of flat), which seriously buggers up some of the carols, eg Good King Wenceslas. However, if you are pissed enough, nobody notices!