I remember Big Art built a Casburn SE-5A profile that was astounding. It would easily out-pattern a Ringmaster, probably came closest to a un-flapped Magician or similar bird. Did not really have any vices, I KNOW I have campaigned full-stunters that did not fly as well! As I recall the outline is pretty close to scale, with equal sized wings and relatively thin airfoil, no flaps. If I was building a Bipe for stunt I would use that one as my starting point.
He has re-covered it at least two times since the original build and I think it is still RTF some 30+ years after the first build!