I use two 722k receivers in our coach. This allows complete usage by either the front tv or the rear tv.
I don't know where you're getting the info that you can only use a 211z...that's malarkey, and I sure wouldn't take any more advice from that source.
In the electronics cabinet, I take cable #1 from the Winegard Trav'ler (DISH 1000)and connect to a splitter that feeds the #1 input and #2 input on the first DVR and connect via HDMI to the front tv. I do the same with cable #2 for the other DVR for the rear tv. This allows both tv's to have HD and their own separate recorder which allows us to watch a recorded program while recording two others...or watch a live program while recording another program.
These same two DVRs I also use in my home utilizing the exact same hookups, but each DVR also drives a 2nd tv. I can remove each DVR from the house and install in the mh in a matter of 10 minutes or so. Really simple. Of course, we spend 6 months at home and 6 months in the mh. When changing from one location to the other, I just get on-line at MYDISH.COM and connect to their chat line and have them change our "service address" and leave the "billing address" the same. I've tried calling them on the phone and would always have lots of problems with the person answering the phone. Many times it was obvious that English was their secondary language and therefore very difficult to understand what they were saying, much less them understanding what I wanted.
Works for us.
Ron