My advice is to start drinking heavily from that shot glass--not water, either. Are you aware these are leaf shutter lenses? Any clunking around is the mirror which, if locked up, isn't in play. Never any issues with my Bronica SQ-B at slowish speeds, or my Mamiya RB 67. Any vibrations you're fretting about are likely post-exposure. At any rate, do you have any images to confirm vibration-related softness? It's never been an issue for me, especially with mirror lock-up.
Originally Posted by emtor