I've revised my previous method for modifying a pair of space boots - still using the same fabrics (black PVC vinyl and silver stretch lamé) but also sandwiching a layer of heavy buckram in between with spray glue. Then I cut my pattern out of all three layers and edge-stitch (about 1/8") along the zig-zagged side only. I then peeled back the PVC and lamé to trim the buckram out of the base.
I attached the PVC to the outside of the boot first with e6000 glue. Clothespins or hair clips will work great to keep things in place while drying.
Once the PVC is secure on the outside I glue the lamé to the inside of the boot. Because the inside circumference is a little smaller, it might have a couple wrinkles.
Finally I roll the points down and secure them with clips for a couple minutes. When they come out, the petals will retain a nice curve without the aid of a wire.
My pattern has also been revised with longer petals. You can download the new Boot Topper.pdf from here.