The SEC will most likely sign a GOR when the SEC branded ESPN channel stands up next year. As I've said before I don't think that a GOR makes a conference stable, rather it's something stable conference tend to do. The B1G wasn't any more likely to lose anyone before it signed it's GOR and & don't believe the SEC will be any less likely to lose a member after they sign theirs. The odds of either conference losing members was alwready effectively zero.
Duke may not add any new networks in NC but Duke BB would go a longer way towards penetrating the NY market than anything the B1G currently has. Duke is the BB equivalent of Nebraska, it's a national brand.
You can do pods with 18 (or 14 etc) just as easily as with 16 or 20. The pods just aren't all the same size. For example, 18 gives you two pods of 5 & two pods of 4:
E - Penn St, Rutgers, Maryland, Virginia, North Carolina
N - Ohio State, TSUN, Illinois, Northwestern
C - Notre Dame, Sparty, Purdue, Indiana
W - Nebraska, Wisconsin, Iowa, Minnesota, Kansas
E/W & C/N are never directly matched up. It's always E/C & W/N or E/N & W/C.
So:
Leaders: Ohio State, TSUN, Illinois, Northwestern, Penn St, Rutgers, Maryland, Virginia, North Carolina
Legends: Notre Dame, Sparty, Purdue, Indiana, Nebraska, Wisconsin, Iowa, Minnesota, Kansas
Then switch to:
Leaders: Ohio State, TSUN, Illinois, Northwestern, Nebraska, Wisconsin, Iowa, Minnesota, Kansas
Legends: Notre Dame, Sparty, Purdue, Indiana, Penn St, Rutgers, Maryland, Virginia, North Carolina
Rinse, repeat.