Try going to your local "big truck" dealer. Kenworth, Peterbilt, Freightliner. They all use very heavy duty rubberized exhaust stack hangers. Much more wieght capable and very flexible. It might take a few minutes with a creative parts person but I bet they will find you something that will work.
I have used all kinds of big truck parts on my Lone Star kit.
Oil cooler, sidepipe mounts,
oil lines, etc.