Back in the 80's, I as a qualified instructor commenced work with an operator on a twin turbine greater than 5700Kg. I was one of the initial Captains and we did our endorsements with a factory pilot overseas. When the other Capt moved on, I obtained C&T on the type. To do this, I had to fly with an FOI who was already endorsed (by the other Capt), and carry out various endorsement sequences as part of the training approvals etc. The FOI then flew the aircraft on a regular basis and the then CAA paid for the aircraft use. Often he would attend a base check conducted by me, then do my IR renewal followed by a base check on the FOI. We would then stand down the F/O and he would operate the line flight scheduled for that day. It all worked very well. Being greater than 5700kg we did not have some of the performance issues that the Conquest or similar types (<5700kg) might have. Many of the comments on this thread are very valid and it shows that training in the aircraft must be managed in a safe and proper manner.