Yes, the old you change one thing and then three things interconnected have to change... For this application time and the biggest effect for the simplest change would pay the largest dividends in time vs. effect. I've seen what one owner did by filling in the mount voids with a rubberized epoxy IIRC- though that is a little too "woodshed engineering" for my taste. Analyzing whether the mount is compressed or operates in tension would be the first step- and you obviously have been thinking about it already. Wonder if making or extending the bracket the mount and/or dog-bone attach to ( the mount attaches to the dog-bone? ) and attaching a stop bolt on one side to limit the mount movement or dog-bone deflection might work and would be a simple modification. I'm trying to picture how the dog-bone is situated with the mount and how spacing it out further would limit deflection?

Steve