Cavok is pretty accurate...... If you go airbus I would not count on many
nightstops or days off (ie 8 or 9) until you get 340 quall'd and even then very limited. Several buddies on 330 only have not had layovers in over 4-5 months. It used to be your first 6 month PPC would be 340 training, that has not been happening lately. While some are going 340 others are staying 330 and seem to be held back for 380 transition which for some has taken close to 2 years. Keep in mind this is not your choice and there seems to be no rime or reason to it, luck of the draw if you will.....Boeing meanwhile is a different story, to a certain extent. Stretches of days off can be had in exchange for doing ULR's which you will have to be acclimitized for. Making it back home is possible but I would not count on it. Some of our highest load factors both paying pax and staff are to the UK, sure there are many other carries flying London routes but they are doing it for a reason, loads.... Good luck with your decision.