You may want to look and make sure that the flap elevator movement is proportional. In other words, make sure that if the elevator moves up 30 degrees, and the flap moves down 30 degrees, then when the elevator moves down 30 degrees that the flap moves the same 30 degrees up. Insure you have symetrical movement in other words. I trust you have checked your lateral balance, as in tip weight? how long are your lines? and how fast are your lap times. One other issue, if the plane is to heavy,, for a twister I would think about 45 oz would be a HIGH number, then you could be stalling it as you try to turn, and it cant turn when you want it to. it will just mush into the ground. If its fairly heavy, then you want MORE flap movement for the same elevator movement, not less. this will help generate lift to turn the plane.
If you want, I can PM you my phone number and we can chat live that way,, maybe we can work up a plan of attack, not that I am any great expert, but it wasnt long ago that I was right where you are now,, like two years maybe?