This is the basic method to set maneuvering speed:

The Maneuvering Speed is the minimum speed at which the wing can
produce lift equal to the design load limit. (in positive G's) Below
this speed the wing can not produce enough lift to overstress the
aircraft, no matter what angle of attack is used.

Rough air speed is generally set so that a certain limit of turbulence
will not over stress the aircraft.

Todd
3S