I have just finished assembling as pieced medallion quilt top for my daughter in law Juli.
During this process I have realized that I have developed a few design tips to make the assembly easier.
1. Make the central panel square . Here the inner light green boarder is wider on the sides than on the top so that the panel is square. Check this after sewing as any small variations at this stage will be multiplied as you go out though the concentric rows.
2. Have a design with some plain rows to make minor variations in piecing easier to compensate for. To explain : while I try to sew with 1/4 inch seams in a long run of blocks what should be 40 inches is actually 42 inches. So that the blocks meet up an match I increase the width of the previous plain boarder rather than restitching all the blocks.