I'm thinking of having one of my duets tuned to fifth comma mean tone. The two questions I've been thinking about are (1) what keys will I be able to play in and (2) how will it sound with other instruments? To help me understand these questions I've drawn up the table below.   (1) I've opted for two flats and three sharps, putting the wolf fifth between G# and Eb; which is where the table breaks the "circle of fifths". Assuming one can use only scales that don't cross this break, that neverth