It will depend on the aircraft and the airline, but over many years on the 737 my experience was that in most cases of turbulence it was pretty simple to set a speed in the middle of the allowable range. If the weight and altitude meant that the range was a bit tight you asked for descent to a lower level. Maybe I was lucky but I cannot ever remember coming close to pre stall buffet. Whereas in the days when fuel was a lot cheaper cruising often at Mach .81 we would regularly go into overspeed. Whilst it was no big deal it was a lot easier to keep off the safety pilot's radar by dialling the Mach back a bit.