Old and Bold RC PILOT
That matches my experience - I really noticed the performance difference with the Mini Arrow and Eluminator flying wings.
To make the wing extremely robust a couple of CF tubes buried in the wing would make it very hard to destroy. The streamer could mount on the rear centre fin as per standard or conventional aircraft.
TO make best use of the extra weight of the second motor differential thrust could be included to allow the bird to almost spin horizontally in level flight or even snap into a banked turn when required!.
Just a thought!