In reply to humptydumpty:
My understanding is that an "off-width" is the size range that is too large for fists, but too small to get your body into. Once you can fit your body into the crack, that is the start of "squeeze chimney".
Also, "squeeze chimney" is not, necessarily, easier to climb than "off-width", both are awful, ugly, physical, flailing type climbing where you fight and fight and fight for hours on end, and find you've made 3 inches of progress.