My dad actually owned the prototype G300 before selling it to a husband/wife team that worked for NASA. Tragically, she perished in what was believed to be caused by a health problem in flight.
The fuselage design went on to be used for the MX line, according to my dad.
When I had my R/C G202, I always liked having a plane that no one else had. Folks couldn't believe how solid it was in a harrier and hover. It drew smooth lines in IMAC, (despite my efforts) and was a really solid performer. I think a few bad R/C designs kind of ruined it for us in the R/C world. The early designs that were mass-distributed were heavy and had a bad tip-stall tendency. It's actually not inherent in the wing design. In fact, the opposite sweep, such as in an Edge, is no more stable. It all depends on the individual design. I've flown plenty of others' Edge's and Extra's that had bad tendencies toward tip-stalling and rolling out of tight loops as well.
I say build the Giles wing, try it out, and see how it goes. If you don't like it, try the MX-style wing.
Can't wait to see the build!
-Patrick