Ok, I would do 7 stars across, and 8 rows. This will make your quilt 88" wide x 91.5" long (approx). It will give you about 1 star hanging down on each side and at the foot (no pillow tuck). This will require 52 stars in all, arranged 7/6/7/6/7/6/7/6/7/6.
You will need 104 triangles of each of the 6 colours in the star. At 49 triangles, per yard, 2 1/4 yards should be enough, but I would do 2 1/2 yards each to be on the safe side.
You will need about 310 whole background triangles, and 50 half-triangles to square up the edges. I would cut them whole and then trim off when it's all assembled, but that assembly method is really up to you. This will be about 7.5 yards of background. Again, I would buy 8 yards (or even 9), just to be safe.
Have fun, and post pictures when you're done!
