More urban legend I see.
"airbrake"...
The vee-angle is dictated by the control system.
A rudder-elevator plane needs less angle between the surfaces than an elevator-aileron plane to get effective turning action, which may or not have rudder as a seperate control.
90° works well in the first case, 110° to 120° for a plane with rudder function, and 135° performs quite well with elevator-aileron only.