Just got there in time today to catch the 1302 service with just barely a couple of minutes to spare. Saw it was a 442 so jumped on. Problem was it was only a 5 carriage train and allready very busy. Had a job to find an available window seat(I am not very keen on aisle seats). Only available window seat I could find was positioned between a window panel and window. But made do with that. By the time it reached it's first stop of Clapham Junction it was standing room only. I estimate there was probably at least 100 odd people standing all the way to Brighton. Aside from that though, a nice journey on a 442 instead of a bland 377.
I worked out that the 1302 service from Victoria would be the very same train to be used for the 1734 service from Brighton. 1302 Victoria-Brighton, 1434 Brighton-Victoria, 1602 Victoria-Brighton, 1734 Brighton-Victoria. And I was correct in my thinking. When I arrived back at Brighton station at just before 5pm, I could see the 1700 service to Victoria was a 377 so I didn't board that train! The 442 shortly pulled in which formed the 1602 from Victoria. I got a head start to get a desired forward facing window seat, by boarding the train before the platform number was mentioned on the departures board and before all the crowds descended onto the train. Anyway, it was a very busy service again. And again many people(easily at least 100 people) were having to stand up for their journey from Brighton.
So going by what happened today and providing it works like this every Sunday, then on Sunday's a Class 442 set should definitely be working the following:
1002London Victoria-Brighton
1302 London Victoria-Brighton
1602 London Victoria-Brighton
1902 London Victoria-Brighton
0834 Brighton-London Victoria
1134 Brighton-London Victoria
1434 Brighton-London Victoria
1734 Brighton-London Victoria
If you want to avoid the 377's then don't travel on the following services:
0932 London Victoria-Brighton
1232 London Victoria-Brighton
1532 London Victoria-Brighton
1832 London Victoria-Brighton
0800 Brighton-London Victoria
1100 Brighton-London Victoria
1400 Brighton-London Victoria
1700 Brighton-London Victoria
2000 Brighton-London Victoria
The services at times not mentioned above(i.e. the 1202 from Victoria), I'm not sure whether they'll be a 377 or a 442. But a posting elsewhere on here does mention that all the xx:02's from Victoria and the xx:34's from Brighton are Class 442's.
Hope this helps.