Yup - a balance of say - 20% to 0% is the best fix.
I hardly ever seal hinge lines and also don't add $400.00 worth of servos and linkage to try and control bad aileron setups .
After much testing -I am now ready to go back to ONE servo to drive both ailerons up to 35% models.
The setup will be cf pushrods to ball end connections on a L shaped bellcrank each end.
Flaperons are a feature I never use and differential is no problem on light models .
Just use equal throws .
Believe it or not -this is what full scale aerobats use- and you can roll em with two fingers of pressure.
On our bigfoamies (up to 400sqinches and 15 ounces ) we can go full speed with no aileron flutter -with one puny 6 gram Bluebird servo .
and roll instantly
We used single aileron servos for years on early pattern models -the ONLY problem was when using those lousy strip aileron torque rod setups
Worthless.