Both shades were trimmed around the perimeter with Samuel and Sons tapes. We mitered the corners, and the blue shade featured two layered tapes.
From past experience with wool shades I knew the layers needed to be interlocked internally to support the wool and keep it from sagging.
First the interlining was interlocked to the wool face. We used the seam in the face fabric and then interlocked in alignment with where the rings would eventually be sewn.
Ribs were sewn to the interlining to provide additional structure.
The lining was interlocked at the board line.
The ribs were secured to the lining, then the rings sewn in between the ribs. These little tack stitches are visible on the back, but they lie on the column line with the rings so they're not noticeable.
The side hems were sewn by hand, and the bottom finished as per my usual method, with buckram in the hem.
To miter the trim corners, we first basted by hand to make sure the pattern was well aligned. The corners were then sewn by machine, cut, clipped, pressed, and the little fiber ends stabilized with some tight little stitches and a dot of glue.
The mitered trim was sewn by hand to the outer edges with a ladder stitch. How the pattern falls on a pattern like the Greek key is a matter of math and luck; for this shade, we had pretty good luck!
Because in both rooms the underside of the boards are not easily visible, we did not need to make returns, but we did use a bit of trim to cover the ends of the boards.
The time we spent on steps to support and stabilize the wool were well spent.