When using stitch and flip you can also stitch a second line 1/2" apart
to make another half square triangle...instead of going to waste. If the
flying geese is very small then I don't bother. But that's just me.
http://quiltville.blogspot.ca/2011/0...triangles.html
I suspect the instructions to use all triangles is to save on fabric.
The downside to sewing triangles is that you will be sewing on
the bias which tend to stretch.