Hi, Craig:

Composer doesn't have a default number of systems per page, but rather has a Page Layout view that lets you adjust each page.

Simply click on the Layout tab that should be just under the metronome icon.

Composer automatically fills the page to what it feels is the best advantage. You can then adjust to suit yourself.

The icons you'd be most interested in (in Layout view) would be the 6th (Force page break at mouse click) (or keyboard "pb") and the 7th (At mouse click keep system with previous on same page) (or keyboard "ks"). These two will let you set the number of systems you want on each of the pages.

Combine those with the 3rd, 4th and 5th icons which govern how many bars appear in a staff, and you can set the things very precisely.

Good luck.

David