One concern before flight....if you haven't already flown it.
I balance ALL my flying wings at 16% then move back from there....
Standard practice for a flying wing CG is 16-20%
The farthest I have heard is 28%...but that was using a computer with optical stabilized active control.
As they always say..."Better nose heavy than tail heavy".
Wings have a tendency to be VERY pitch sensitive with aft CG's and you have PLENTY of surface area for "elevator" control on those elevons.
I have posted a simple CG diagram for wings on my page here:
[link=http://home.comcast.net/~crazyherb-rc/]CG on Wings[/link]
Check out some of my other sucessful projects and good luck...it looks like going to be a hoot to fly!
PS - I could have built that plane in 2 hrs out of foam...
CrazyHerb