I also have a Galibier (Stelvio) table and have had a friend's ZYX mounted on my Triplanar. We did not experience the woofer pumping you are experiencing. Your CRAZ rack is an amazing product. I wonder if it would be worth a call to Kevin; perhaps he could point you in the right direction. As an aside, my turntable sits on a GPA Monaco platform on a EquaRack. Perhaps the EquaRack product might be worth exploring.
BTW, great information on this thread.
BTW, great information on this thread.