This is all great stuff.
I found a major clue to my failed recordings/missing guide data issue (you may notice another thread where I suspect the switch in the LNBF and am replacing it with SWM just on general principles).
Non-SWM at the moment, I have four cables coming from the SL5. I plan to reuse one of them. There are F-81 barrels in all just behind the dish, as the cables were there for a nearby Phase III dish replaced in 2007(?). I opened and inspected all four, and found some minor discoloration, which I burnished and then reconnected all four. As I was checking signal on sats on all four DVRs (which I figured I might want to do in case the signal interrupt made one go stupid) I found this anomaly on one DVR:
On 103s and only on one tuner, all transponders were missing. Not on other DVRs, which rules out the LNB part of the feedhorn, but not the switch part. I changed the sat setup to some weird sat, rebooted, and then changed it back to SL5, hoping that would blow out a corrupted config, and restore a good one. Just after the reboot, the transponders were no longer missing.
OK, that means it could be the DVR, or it still could be the switch. I already ordered the SWM SL3, so that will pretty much narrow things down if I continue to have issues. Probably a good opportunity to repeak anyway, which has not ever been done.
The missing transponders included those from the local spots (thanks, dpeters, for the spreadsheet). And those were where the failed recordings were (Elementary, The Crazy Ones, Tomorrow People).
Thanks everyone. It's nice to have detailed sat info when troubleshooting an intermittent issue this surgically.