Whatever pattern you use, remember that not all 1/4" seams are equal and all blocks submitted may not be equal either. Choose something that when squaring up, you won't be cutting off points or messing up the design. Let's face it, not all of the points done by the same person end up in "perfection" so why expect the stitching of a group be perfect either. Make it easy, whatever you choose. A lot of the attraction, especially to the non-quilter, to a quilt will be in the fabrics/colors chosen than in the stitchery.