My current setup uses 2 sw21's to feed my 2 dishes to 2 receivers. When I get a 921 I'll want to add another line for it's second tuner. I planned on Dishpro swith and may need an adapter for the 921. Can anyone let me know what is the correct switch is that I'll need. My current setup is one 301 receiver and one 6000 with 2 dishes so I can get cbs-hd.