I could be wrong, but from what I gather, all of what they're holding for rush now are VERY obstructed. You know, if you don't mind potentially wasting a bit of time, you could try your luck and see what's available at History Boys for rush. If they're crap, you'd have no problem skipping over to Inishmore and getting rush there at 10:30 or whatever the time would be, getting out of THB. Just ask where the rush seats are, and especially if they're on the far house right side near the front orchestra, I honestly wouldn't bother (and this is coming from a HUGE fan of the show). I'd suck it up and stand for the 2 hours 45 minutes before I'd sit in those seats again. I'm honestly don't think I'm exaggerating when I say that at least half of the stage is obstructed. Plus, if you're in those house right seats, whenever the piano is played it's really difficult to hear anything else (particularly sad to miss Samuel Barnett's numbers).
And re: Inishmore's seats, they're great! I've rushed it 3 times. The first time was in previews and I was in the orchestra, way on the side. The other two times were in the mezz in the side sections, but the view was wonderful. The time I went on a Friday, the theatre was full, so we had to stay where we were (in the last row of the mezz), but yesterday, we moved down to the third row of the mezz (could have sat in the 2nd row, but opted not to bother having someone right in front of us and left a row open).
But when did New Hampshire become--Such a backward wasteland of seatbelt hating crazies?...I mean, only 40 people actually live there. The others are just visitors who come for the tax-free liquor and three inches of novelty coastline. John Hodgeman on The Daily Show (1-30-07)