I can't help JJ with his/her concern, but, Liland, I agree with you about Gregorian chant and the failure of the program to follow beyond the edge of the page. What I do in that situation is widen my song window to full screen width, then place my bar lines at the extreme right of the screen, clicking on the bottom slider bar ro move the screen a full width right at a time. This allows for a minimum number of bar lines and causes the program to follow the notes.

As for the last line, if you open page setup and click on 'Options' there is a check box called 'Extend Last System.' Check that box and the last line will extend across the page. Then you need to play with staff sizes, fonts, margins, etc., to actually make the notes fill that line.