A late reply to my own post, but just got back from the trip:

At 1100 I asked a woman at UA CS center and a man at UA checkin about probable lines at 1600. The woman was completely irrational and wailed on and on about "government security" being "out of control of the airlines" and said "We can't force you to stay in the airport but . . . [we recommend it]" and that I should be back no later than 1400-1430 for a 1730 flight for which I was already checked in. The guy at checkin was more reasonable but still said be no later than 1530. I politely complained about the lack of an elite security line, and he blamed the TSA but said UA was trying.

Got to the airport at 1550. Line was backed up to UA ticket counter with a guy with a giant tall yellow flag marking the end. But as other posters said, it was really fast. So fast that I really never stopped walking (at high speed) through this huge wrapping line. Got through in 11 minutes and was fairly pissed (to clarify, not at TSA) as I probably could have spent another 45-50 minutes visiting with my family.

I suppose the one-line for 10-30 checkpoints system is valid, and from a queuing theory standpoint better because one slow checkpoint can't cause a huge backup, but there's got to be a way to make the delay consistent and understandable. A 5-10 minute line is acceptable, but I shouldn't have to worry about showing up 3-4 hours early for a flight because it's so physically long or it might be a "bad day."