tootler, you are right it is a personal thing,I find 147 perfect as a hornpipe metronome setting,Jack prefers something else.
if we met ,and Jack started a hornpipe I would listen to him and play his way,If I started a hornpipe I am sure he would do the same,there probably wouldnt be that much difference anyway.
in fact that is what makes the music interesting,hearing the different ways that people play,one thing a metronome is useful for is training people not to speed up,and end up much faster than they started,BUT the player has to accept that the metrornome is right,and listen LISTEN LISTEN.
playing with other people is about listening to them.