After reading the entirety of this thread, I'm left with questions. The warped wing could have trim issues that vary with speed but they have to do with roll and I'm slow to want to believe that a roll issue is what is at play causing ground loops (considering that landing gear are not at issue).

I've owned a lot of bibes and like others, have found that power management is important. Some have required slow increases and others needed hammered. Partly I think its a matter of how prop wash or a cross wind hits the stab until the plane has reached flying speed. Mostly however, I think its a matter of torque that requires rudder offset after the tail comes up.

Observe carefully the track of the airplane after takeoff while keeping the wings level. I'm betting it will produce some left turn. If it does, then it tells that right rudder is needed on the takeoff and climb out. Now takeoff and hold right rudder to track straight (again, keeping the wings level). Note the amount of rudder stick movement needed, probably only a slight bit.

Adjust some right rudder mix starting at one third throttle (or the power level at which the tail comes up) and at full throttle the mix is equal to the stick amount experienced. This should provide a good takeoff without the need to time rudder to match the moment the tail starts flying.

Finally...do a loop directly into the wind to see if the rudder mix affects loop tracking. If not adversely... then nail it down.