In my case its not the back rest but the extra thickness of the seat itself. But in the mean time Utopia has one of my stock seats and is fabbing a bracket and back rest for it as we speak. If all goes well it would be another option for us Tourer owners.
I had a custom seat done on my Honda CTX700D by Loren of Baldwin Saddles, and I told him I would like a Utopia back rest for it, and they worked it out, and now I have one.
I would be interested in your report for the Rocket. I expect to take delivery soon, and that, plus heated grips are high on my list.