I decided to make the finished petticoat trim approximately 50″ wide, since that was almost half the petticoat width and seemed to match the gown photo pretty well. I started with the upper-flounce and gathered each section to about 8.25″ inches. The gathering stitch (running stitch) was centered along the length of the flounce, approximately 3.75″ from top and bottom. This was one time it helped to have so much piecing… it kept the gathering pretty even along the length of the flounce. I ended up with an upper-flounce that was about 50″ long. Keeping the center front pinned to the upper-flounce, I then gathered the under-flounce to match it. The gathering stitch on the under-flounce ran 3.75″ from the upper edge. This kept the top edges of both flounces more or less even. I used a large spaced backstitch along the gathering line to stay the gathers and sew the flounces together.
And that’s still not enough for one day… I also cut the skirting piece in half and created a seam at center back – again to allow symmetry of the stripes. This was then knife pleated at the upper edge with approximately 1/4″ pleats, each individually pinned. The pleats were pinned again about 6″ below that to hold the pleats in place. The skirting was then placed on the dress form under the bodice and the seam line was marked with pins. I managed to get one half of the bodice sewn to the skirting before I gave up for the night. I folded the lower edge of the bodice & lining to the inside and whipped the folded edge to the stitching line marked on the skirting. That’s enough for one day!