For a 1/4 Scale Twin Engine plane, I for sure would us a sufficient power metal gear servos all around, at the minimum a HS-645mg for Flaps and Ailerons, personally I use the digital cousins for all my gas planes,

John, you must have mis read the OP,, I can't see you suggesting using a Mini on a plane that size to save a little weight,, I mean we're talking a 111" wingspan plane here,, with what?? Twin 30cc-40cc Gassers?? A HS-85 or HS-225?? Smaller .25-,40 glow twins,, sure