David - The layout of the Giles is one of the best - but the real culprit is every last one of the commercial kits -of this design -for sizes up to 1000s quares - typically ends up overweight.
The EDGE wing planform is absolutely the worst wing layout for snapping - the saving grace is that the fuselages are much longer than the Giles ( distnce from CG to center of stabilizer)
I helped a friend scratch build a copy of the Midwest Giles --at 10 lbs - this plane was excellent - could be pulled very hard without doing the nasty high speed stall.
We use the same wing on our Dalotels . beautifu aerobatic layout -
In the 80's Hanno Prettner run roughshod over all the TOC flyers , using this layout - the smoothness and crisp snaps were still the best I have seen --and I was Line Chief last year at the final TOC-- so I have had a chance to see a good cross section of designs .
Even CHyde's Bipes have swept LE's