here is a picture showing the size difference between a standard futaba servo and the low profile ones
I am using the low profile servos because I intend to get the gearbox and motor as far forwards as possible, A standard servo will not clear the motor but the low profile ones will,
also mounting them as if I was building the Knight hauler to reduce play in the steering, if I build the delivery truck as according to the manual there is a lot of slop in the steering and not in the USA truck set up