I started cutting a new back for Odyssey's hatch tonight. The first one was about half an inch too narrow at the top, and since I've only got half an inch or so to work with the darn thing doesn't fit. This time I'm cutting and fitting each piece individually, and it seems to be working out so far.
I cut the two sids, they are just slightly different angles. Not enough to make up all the problem at the top, but enough that I needed to reset the miter gauge on the saw before I cut each end of the bottom piece. I had to go in to make dinner before I cut the top, but I'll do that tonight and see what it looks like after I glue it up.