Sorbothane is good stuff in the right application but here won’t it make the mount very sloppy?
There is a great application guide for Sorbothane here: https://www.sorbothane.com/Data/Sites/31/pdfs/product-guides/Sorbothane-EDG.pdf and an even more useful design calculator here: https://www.sorbothane.com/Data/Sites/31/edg/vibration-calculator.html Generally what is important is to compress the Sorbothane by 15-25% for best performance – so you pick your area to give you that compression for your given load.
Martin