I think I understand everything I need to about the SWM8, but I want to be absolutely sure before I shell out the cash. Up until last Saturday, I had a standard DirecTV setup with a 3LNB antenna, 1 std DVR and 2 standard receivers supplied through a 3x8 multi-switch with an OTA input from a local antenna. I had diplexers at each TV to split out the OTA signal and to feed my FM receiver in the living room. When the installers came to upgrade to HD, they replaced the antenna with the Slim LNB5...four cables coming into the house to a 6x8 multi-switch. I now have 1 - HD DVR (HR23-700), 1 standard DVR and 1 standard receiver. However, because the 6x8 doesn't have OTA input, I lost my antenna feed to the other non-DTV TV ports in the house and to my FM receiver. I can't run additional coax because all rooms are finished and not easily accessible. SWM8 looks like the solution! I think I need... 1SWM8 with power supply, 1 1x8 splitter, and SWM compatible diplexers at every location where I need to access the OTA signal...is that right? Anything else I need to make this work?
Questions: 1) If only SAT 1 input is used on each of the DVRs (1 HD, 1 standard), how does the DVR reconfigure for the two tuners to operate the same as now? 2) For TVs not connected through DirecTV box, do I need the diplexer just to block the DC signals from the TV input? 3)If I can free up the second coax run that I have to each DVR by using the SWM, does it make more sense to use that second cable for my OTA feed and instead buy SWM5?

Long and wordy...sorry!