Joel, I can't answer any of your questions but applaud your decision to make a hard buck. I've wasted YEARS of work and rework because I did not take the time to make a hard buck which would have forced my panels to be symmetrical.
I love flexible shape patterns but without something to tell you HOW they fit to the next panel you can get out of symmetry in about half a heartbeat. Ask me how I know...
I'm at the point where I'm still not sure if I should continue on with work that I'm not happy with or bite the bullet, scan one side, have someone make it symmetrical, and get a buck made and start over. I'm not sure it wouldn't be faster even as far along as I appear to be.
Good luck. Your project is going to be awesome.