I asked because you’re coming from HD25, so must have some affinity/trust of Sennheiser. I have the HD600 and I love them, I don’t know where my bonce dimensions fall on the spectrum (I wear a M/L bike helmet, if that helps)
The hd600 headband doesn’t clamp me at all. I sometimes forget I am wearing them! Compared to say my Beyerdynamic DT-880, which you are always aware are on your ears.