I actually finished Nymphalidea on Sunday afternoon.
Once I got to 18 repeats of Wedge D, I started decreasing at the top edge to dramatically slow down the rate of increase.
I worked until I had 36 repeats of Wedge D, then I worked two rows of the solid color so that I was back at the top edge, then picked up and knit stitches long the top edge. When I had 2 stitches remaining, I slipped those 2, picked up 1 at the beginning of the top edge, and passed the 2 slipped stitches over — decreasing 2 stitches. This was to lessen the “corner” at the junction of the top edge and the live stitches on the needle. Then I continued picking up stitches along the top edge until I had picked up all the way back to the start.
I then turned and worked a 3-stitch applied i-cord along the top edge, attaching to the shawl by working the third stitch together with a live stitch from the stitches picked up along the top edge.
Important tip: Miles of applied i-cord goes much faster when you have a little helper.
When I got to the junction of top edge and lives stitches, I once again decreased 2 stitches in the same manner as above, as I continued to work the applied i-cord. This pretty much gave me a straight edge, no corner at all!
To block I steamed the piece carefully with my steam iron, opening up the lace wedges as I worked. The finished shawl is about 88” along the top edge — nice and long!
“After helping Momma with all that i-cord, I am exhausted!”