Tilt servo size recommendations

Im beginning a design of a Y3 style vtol plane(2 front 1 rear). The motors will be T-Motor MT4008-12 from an earlier project. Estimated weight around 4kg. I imagine the gyroscopic forces may me quite large to tilt a motor.
Can someone comment if they have had problems with servos being overpowered or gears stripping. Ill probably use standard size servo but just wondering if I can get away with the next size down (mini), if chosen carefully.
As this will be my first vtol project (many multirotor and planes so far) I am wondering about choosing props. Clearly they cant be perfect for hovering and fast forward flight. I was considering having the rear motor used for forward flight and having a larger pitch on it, but unloading it in hover by having a forward CG.
Comments welcome.