Thanks for comments.
I made the back about 6" above the tailgate to match the teardrop template. I may be able to go a little more aggressive and curve all the way down to the tailgate - but I wanted to err on the side of caution. I'd rather have a little extra drag than have detached flow at this point in time.
As far as curving the end, I don't know if that would help or not. I've read it can be good to have a clean separation point at the end - but I don't know for sure.
Good luck on your build!