I used the "fast 45" method which makes one unit when I made my River Trees avatar quilt. A little waste but sharp points every time.
http://www.quiltingboard.com/picture...s-t230754.html
http://www.quiltviews.com/river-tree-the-quilt
Then I used the method that makes 4 at a time for a Northern Journey quilt. No waste!
http://www.northcott.net/images/quil...20pattern1.pdf
Both worked well for me. I avoided making them before I found these methods because I had the same problem you seem to be having...they always stretched. Ugh! Now they're easy.