For Y seams, you need to stop sewing your seam 1/4" before the edge of your material. Be really careful not to stretch out your bias edges when you are manipulating your quilt around to put on each diamond. I know there is an 8-point star done with strip piecing then cutting on an angle - check this out:
http://www.quiltedparadise.com/n/magazine-59.jsp
Just found this too:
http://tutorials.missouriquiltco.com/list/