It's not "dumb thumb", that would be knows as "fat fingering it" hahaha.
And, start out with your swash mix at 60. Check to see if there is any binding. Be sure to do full left and down, right and down, left and up, right and up. That will check all of the throws. Also look at the rods and make sure they are not binding. It really just depends on how twitchy you want it (expo is a must if you want max throws, and still be flyable), and how fast you want it to flip or roll.