Sorry to be blunt but the answers - such as they are - are in the various BA threads (I know - I've posted them before!)
There is no set roster as such. If you expect to work weekends, bank holidays and get up early, you'll not be disappointed!! But then, expect that, once published, it is highly unlikely to change. And, in reality, you'll get a good mix with a degree of choice (bottom 20% of the fleet, 3rd choice this month).