Steve:

Just a note that we climbed and summitted on Monday, using day use permits. I wanted to thank you for your help with info. FYI, although I know the odds were very good about unused permits being available on a walk in basis, with the distance involved in our case and expensive flight changes (change fee plus increased fare, about $200 per person, plus the uncertainty of when the next available flight might be), I wanted to hedge our bets. I kept checking the website, and all I could get in advance was one day use and one overnight permit (you will recall the ham and cheese without the cheese). Upon arrival, the rangers did not like that since it might deprive someone of getting on the mtn, but they had a day use permit available (about 1:00 pm), so they converted (or whatever) the overnight to a day use. All the same to me.
It was a long brutal day, but we got up and down and it was great. So thanks again for your help and info.
Larry