In my internet searches, a few years ago I ran across these Polyurethane/Stainless motor mounts. They are perhaps similar to Butler's product (or also made by them for Butler?) While somewhat pricey, these should last much longer than the reproduction rubber mounts, and they eliminate the need for a turnbuckle because the steel parts interlock, but are isolated by the urethane. So a mid-point between solid mounts and the OEM style rubber mounts.
Interesting design, independent vendor perhaps worthy of support
https://polybushings.com/pages/2254.html