Wish is same capacity as Dream and Fantasy. We were just there the week after Thanksgiving on the Dream on a SOLD OUT cruise. No issue finding multiple chairs together and plenty of beach space for the kids. I heard one of the cruise directors when we were on the magic say that there is like 5 chairs per person on Castaway for the Magic but then like 2-3 for each person on the larger ships. Gotta think that includes kids that don't use chairs. So PLENTY of chairs.
Now if you're wanting front row, hustle off right at docking and get your prime seating. You can see the beach from all of the chairs tho so its no biggie LOL!
Just relax and have a great time.