I replaced my bushing with the brass one. When I reconnected the coupler in the back I encountered some resistance when I raised the end of the rod up. I did some looking around inside the tunnel with a little scope attached to my cell phone. Ultimately, I decided to live with it.
The price of the brass bushing installation tube does seem outrageous. But, if you consider someone's time to hand make it, it seems a bit more reasonable. If I can find it, I would be willing to lend it to anyone who wants to install the brass bushing.