From what I remember it was approx 2/3 weeks initial training per aircraft. There are requirements set down by the IAA and the same is said for the CAA and the FAA. In fact I remember when EI operated a wet leased American MD11 (World Airways I think) which flew from SNN to JFK for four years during the peak Summer seasons. The cabin crew were required to follow an initial MD-11 course for three weeks. Just for that aircraft. The following years they were required to follow just a four or five day refresher course. Similarly EI wet leased an L10-11 from a UK company and the crew had to follow a similar course for a similar length of time. There are set out procedures/curriculums to ensure that every part of the aircraft is known, what each piece of equipment does and how it works and if god forbid there was an evacuation that the crew know exactly what to do and when to do it. Before the crew are signed off/certified they must do at least one familiarisation flight that lasts at least one hour 30 mins as an extra crew member to observe and ensure that they understand the workings of the aircraft - as required by all aviation authorities although times may vary.