I went down to the NB line at about 8:30am (Friday) and it was so, so, so long and decided not to wait.
We were staying at the DL hotel, so I walked back by at 9:20am and literally walked right up to the podium to make an appointment. The confirmation had an estimated wait time of 4 hours, so we went to breakfast, expo, DTD (non-park day for us). They do give you a link in the confirmation to check which group they are on and inventory levels.
Received notification at 1pm to head to the NB booth at the expo and after waiting behind about 5 people, tried on the shoes, went straight up to pay. Easy, easy, easy!
I was completely fine with the 4 hour wait between appointment and sign up because of our schedule for the day and the close proximity of the expo to DTD/Hotel. Had it been at WDW, I would not have wanted to stay at WWOS for 4 hours waiting for the shoes.