If you are not going to beat on your plane,using 4.8 (lighter) and the servos you have,you will be fine.
Have solid no slop linkages and seal your gaps with some tape and the strain on the servos is lessened also.You can do KE and if the servo is weak you will notice blowback in flight and can get a better one when you have time and xtra$.
If you fly smoothly,meaning no full speed snaps,blenders etc,your stuff will work fine.