I think it's actually T-354 actually for BA metal and some partners, at 01:15 hrs London time, but with some many sectors over various time zones your 331 may be nearer the mark, not least due to the later release of some US routes. I think this is going to be a tricky one, and I guess you are trying to book the brain-frying trans Pacific routes - to go via Cathay or Qantas from LAX, YVR, JFK (etc) via HKG or SYD. I think one key decision to make is whether you are prepared to hook the biggest sector(s) earlier, if it is available, then pay change fees to get the extra segments, or keep them on separate bookings as other options open up. I hope you are not also trying to use a Companion ticket in this!

Welcome to Flyertalk Judy795, welcome to the BA board, and please continue to post, it's good to have you here, we like to see new faces in this forum.