If you are going to do it I would recommend you book it sooner rather than later. This is the third time we have stayed on site and have always used the preferred viewing, booking it when the pack arrived (I don't think I knew you could book it at 180 days). Well, our paperwork arrived on Friday for our 10 trip starting on 31st and I called yesterday to book and Wishes is fully booked throughout the trip! I wonder if it has something to do with the amount of parties as it was never an issue before, the first time we were the only ones in there and the second there was half a dozen of us. The agent said Wishes always books quickly. I'm not that fussed as I don't think it's the best viewing area but it is nice to be out of all the hustle and bustle. Oh well! We did get Illuminations though.
One other thing, although you call on the UK number which has opening hours that are friendly to us option 4 has the same hours as the dining line so doesn't open until 7 a.m. EST.