As a suggestion, before you install the tail srevos, check the CG with the 40cc up front. If the engine is about 3# you should probably use a pull-pull with the servo in the center. If near 3 1/2 # suggest you place the rudder servo in the tail. I have the same plane using a Saito 1.80 fs. Engine about 38 oz. Had to add 8 oz in the nose for a correct cg. This is one awsome aircraft. Have had about 60 flights with only one dead stick due to a loose mufler. Having so much fun with the Saito that have not replaced it with an os 1.6 which I have & can be installed without the extra nose weight. If I loose the 330 I will probably replace it with a DA 50. This engine is over 3# so I would prabably place the servo in the tail for better cg. Heard this combo wil tail slide & torque roll with ease. Good luck!