I followed the instructions and made the same alterations as I did with my first bomber.
The only issue I had was that my ribbing wasn't wide enough to cut my pieces, super annoying! I fixed it by cutting the ribbing pieces in two pieces and stitching them together. Not the prettiest, but for Burning Man it will work :)
I acted a bit stupid when I inserted my zipper into my stretch fabric. I didn't stabilize the edge first and now I have a super wonky zipper :( Its not too noticeable when I close my jacket though so I can live with it.. But next time, I'm stabilizing it! Lesson learned.