Last night I went to put the collar on. First I tried to be lazy and not flatline it, which turned out to be an unsightly mistake. Also, the rectangular shape that had looked fine on the mockup didn't work very well on the real thing. I changed the front collar pieces to a slightly curved shape. Finally, I wrestled with attaching it using normal techniques, which was a nightmare. I ended up finishing all the edges, butting them together, and whipstitching everything. It turned out much nicer that way.