After re-doing a "great angle" several times to see the way I measured it was inaccurate, not realizing it would be angled the other way, I just used a large piece of material and sewed about in the middle. I figured that way there would have to be enough! It sure wastes a lot of material though.
My avatar is a mariner's compass I pieced. The material for each section were cut out ahead of time and I wasted so much material I could probably make another quilt! I did make one crazy quilt pillow out of some of the fabric and will probably make a bolster pillow out of some more.