I would divide the corners into two pieces, ie; on Jinny's, make one seam from the northwest star point out to the corner (on the diagonal). The other one, the north one, will be more tricky unless you leave more room between the upper star point and the border. You may have to plan ahead for where your border print will get disrupted, at the meeting places I mean, so that the disruption is symmetrical all the way around. I don't know if this helps any. You may also consider assembling the whole corner section before attaching to the octagon. Good luck. Please show us the finished project.