Making half hexies would eliminate the dreaded Y seams, it could be constructed in rows. I would start w/ the 60' triangle (drawn on paper) take and inch (or more depending on the original size) wide wedge off each side add seam allowances to the cut and use those as templates, the center triangle for your colored and sew a white wedge to each side making it back into a 60' pieced triangle, then using those to make your half hexies.