Not being familiar with either you or your plane, this suggestion may be of no use to you. I have several trainers and the roll rates were sluggish, so I decided to experiment. I installed a servo for each aileron and removed the center servo in a Tower Hobbies .60 trainer. It made a world of difference. I don't know how your plane is set up. It might already have dual servos. If not, installing servos in each wing is not really difficult, but it does require a minimal amount of building experience.