Hey buddy not sure if this helps but this past May me and a friend went to Yosemite for 3 days. The first day we stayed in North Pines, the second in the back packers camp then in Little Yosemite Campground.
We woke up early the second day and got in like 1 hour before the back country permit office opened. The two ppl in front of us got all the permits from the valley to LYCG so we were the first in line to get some from Glacier Point to LYCP, but after two groups after us those were taken. So yes some did wait in line for about an hour to 45min.s and didn't get a pass. So if ur going to plan on getting them the day before get to the back country office as soon as u can. We did one hour and just got in. Best of luck. Half Dome is worth it. I got a video of me and my friend at the summit check it out.. search for mtt37849 and the title will be half dome 2009