Another thread mentioned someone getting a SRO ticket on a two-show Wednesday when getting in line at 10am. I just wanted to confirm that this was the case for me, as well. After picking up my rush ticket at Come From Away for the evening show, I walked around the block and got in the box office line for Hello, Dolly! a little after 10:05am. Both me and a couple behind me were able to secure SRO tickets to the matinee. Granted, I got SRO 22 (one spot away from the edge of the padded bar on house left) and the person to the left of me (SRO 20) had gotten in the SRO line at 8am. Still, this should encourage others to try for SRO, even if/when chances seem impossible.
One reason for this (and I'm speculating here) is that, based on what I heard and saw in the box office, most of the older clientele opted for premium seats (or, you know, actual seats) instead of SRO, even though they lined up at the box office with many SRO ticket-seekers. Given the primary audience for this show, that may make SRO "easier" to get for Hello, Dolly! than for other shows with box office lines of similar length.