Dave,
I know that the Madness won't roll for ***** with its wingtips. I also do know that the general concensis or opinnion is, that square wingtips Elevator and Harrier the best. That is also my experience. My HardBet, which basically had a Hershey Bar wing with slightly tapered ailerons, was the best plane I've had at Elevators and Harriers. My 60SuDoKhoi with the SDK wing tips, would rock, but was controllable to Harriers landings. The Extase would rock, and I never did quite get it under control in Elevators. The UCD I've only flown twice, and it was nose heavy both flights. Next weekend I'll wring it out some more and see if a combination of tail heaviness and spoilerons can lock it into an Elevator. My Extase needs a little TLC, maybe I'll square off the wing tips when repairing, and see how it affects it.
DKjens