When I made Palo reservations on the 2/22 Magic, I was lucky to get there early enough that there wasn't really a "line" yet - we went there directly after boarding around 12:15. There was one table for dinner reservations, and another for the tea and brunch times. The CMs directed me to the dinner table first, and then I wandered over to the other table and made the rest. The Wonder may have separate lines for each night because they only have 3-4 nights. With 7 nights on the Magic, they can't really spare that many CMs, I guess!
I'm assuming that eventually a line formed at each table, so if you have two people to wait in line, things might work out better. Or just get to the port early (I was in line to board by 11:00), and you'll only have to wait in one line - the boarding line! I didn't have to wait in any ressie line once we got on board, and I got every Palo resv. and spa appt. I wanted.
Also, I don't think they fill the room for the high tea - there were only 4 tables at our tea (Monday sea day), but I'm assuming that we were completely booked, as they didn't have additional tables set for tea. It was a lovely afternoon, and the scones were delicious!
I believe the high tea is held on the afternoon of each sea day, so the Western should have two high teas, on Monday and Thursday - but there are three brunches, with one on Sunday as well. I would recommend having the tea and brunch on different days, just because you probably wouldn't have any room left after the fabulous brunch!
April
High tea goes quickly but you'll have no problem booking dinner. At check-in at the port they'll give you a sheet that tells you when you can go to book Palo (go early) and you'll have your dining rotation imprinted on your Key the World Card, so you don't HAVE to go to your stateroom first if you don't want to.
