I appliqué the design onto the plain leo with a zigzag stitch (to allow for stretch). Top tip here, spray appliqué with spray adhesive on the reverse ( I use 3M) before applying, holds much better than pins.
If I was to do a design like this
I would cut and stitch.
'Margo
Going back to this design, the technique I would use is what I did on the one I made the other day. Translating what I did into this one, I would sew the orange and black layers together first so that they lie completely under the appliqued white.
I would cut the orange and black so that they overlapped each other by 1/4in / 6mm. I would pin then hand baste them together with the overlap. Using zig zag (about 3 wide on my dial, and 2 long - Bernina machine), I would stitch down the centre of the overlap. Then the basting can be removed. The fabric can be trimmed a little, but there's no need.
I would cut the white swashes out, also tracing the pattern and their positioning onto the tearaway. I'd lay the orange/black combined piece on my ironing board and then place the white swash on top. Using the tearaway over the top (it is see-through), I'd make sure the white swash was positioned perfectly. I then usually pin the tearaway around the edge, nowhere near the applique part.
Then using the iron on as low a setting as I can, I'd gently and carefully iron on the tearaway. If it is not sticking, increase the temp by margins until it sticks. You don't want to go in with hot iron blazing, because we ARE working with synthetic fabric and melting it is just not the idea!
When the tearaway has adhered, move to your sewing machine and zig zag stitch the join of the white to the underneath fabric. Again I use about 3 wide and 2 long. Using white sewing thread, I would position the stitching so that one edge sits right on the cut edge of the white fabric, with the rest of the stitch width sitting on the white. At outside corners I taper the stitch width so that I can stitch right to the end of the point. At inside corners I just pivot.
When all is stitched, you can tear away the tearaway. It takes a little effort to get it out from under the stitching, but it certainly can be done. Tear away from the sides of the zig zag first, then stretch the zig zagging. This means the tearaway inside the stitching will pucker a bit when the fabric relaxes again, giving you (or your tweezers!) something to grab onto to pull it out.
This is how I would do it. Others probably have other methods that work for them. Oh, how I would love to be a fly on the wall in a GK workroom or at one of the other professional manufacturers to glean their tips and tricks!
You should invest in an overlocker if you are making lots LMM, halves the time to make them. 'Margo
. A bit of practice though and I am selling now, I have orders for high school team leo's because I'm cheap and they don't want to be paying for milano etc for a couple of comps and a display per year 
