Tough answer. Each platform will respond differently to a rotor vibe sourcing function. (Depends upon the Xmsn used, the pylon mounts, fuselage construction material and type, etc.) Somewhere there are vibration surveys for each aircraft. Those values are used to set qualification levels of most equipment. You may have some luck using the 'internets' or your local helo Mx contacts to determine a vibe spectrum for a specific area for a specific model.
Good luck.