I suspect you need a good profile to build to. I'm not fond of the profile you showed me in those plans, but if you like it, go for it.
I would much rather take the Generic Benroy plans, and add 2 feet in the middle, (where it is flat on top), and keep the front and back radii cool looking!
Of course if you really wanted to get cool you could do a continuous spline from the lower front corner to the lower back corner. But that's a subject for another thread!
Mike...
P.S. There's lots of 5x10s in the hall of fame, like this one here for example...
http://s147.photobucket.com/user/scrawf ... t=6&page=1
The quality is remembered long after the price is forgotten, so build your teardrop with the best materials...