Don't know for sure, but aren't the Sennheiser headsets usually a little smaller than for example David Clarck?
If so i would recommend something with bigger earcovers. As an ex-ATR pilot i know they make an awful lot of noise, the bigger headsets provide better protection, be sure to check the microphone for correct values though. Chances are the boom fuction will not work correctly if the values are different from the headset of your colleague.
Happy landings.