I don't know that this would help anyone else's research, but I'm kind of curious now about how long the coverage was running at different points during the summer. Do all of these pre-emptions make sense, or might some of them have been caused by something else?
Some of the pre-emptions were predictable, others weren't. For the most part, on weekdays with pre-emptions, coverage was carried from 10AM to 12 noon eastern time, recessed for two hours, then resumed from 2-4 PM eastern time. This means, *in general*, that Password, Split Second, LMAD, Jeopardy!, The Who, What or Where Game and Three on a Match were not as subject to pre-emptions as morning or late afternoon games. But that's only a generalization; I'm sure there were days when the Senate didn't recess exactly at noon and some episodes listed in the New York Times for 12 noon weren't seen. In addition, I wasn't born yet so I don't have first-hand memories ;-).
The rotation plan wasn't exclusive; I believe that any of the networks could carry any portion of the coverage they wished. That's why pre-emptions were so heavy during the week of June 25-29; it was the week of John Dean's testimony and (if I recall the NYT listings correctly) all three networks pre-empted their 10-12 and 2-4 lineups for all five days. That also accounts for the one-week gap between the end of Hollywood's Talking and the beginning of Match Game.
The networks did make some attempt to carry the second round of hearings beginning in late September, but they did so at a much lower rate and by early October had pretty much ceded the field to PBS (except, of course, for major events like those in July/August 1974).
Things settled down during July 2-6; I did not see any indications of pre-emptions in the NYT schedule. The FAQ on G-R.net (which you do an *excellent* job on, by the way) does show TPIR airing on 7-2-73; it was the program originally scheduled for 6-27. Here are the dates on which CBS carried Watergate coverage after MG premiered:
July 12, 17, 20, 25, 30
August 2, 7
September 26
October 3
In addition, 10/11 had a pre-emption for a "Daytime 90" special, 11/22 had "20,000 Leagues Under the Sea" and 11/23 had "H.M.S. Pinafore".
I've checked the known Watergate coverage dates against the G-R FAQ and found three discrepancies: the NYT does show TPIR and MG airing on 8/8, 8/22 and 9/5. I have no way of verifying who is correct for these days. Thus my research into the MG 73 airdates is only preliminary at this time.