Agaricus bisporus - shame on your comments. Yes many did cope with the additional torque of the Merlin however many didnt even back in the 40's and 50's. Your comment that the instructor should of been in the aircraft as well brings you no credit at all.
barit1 - you apparently are aware of the unfortunete pilots history with regard to his previous experiance - if not dont speculate. The T6 route whilst expected is not the only way into the cockpit of a P51.
As far as I can recollect with books to hand is the LouIV was not a TF51 ie two lots of controls therefore Im presuming the 'student' must of carried out the initial landing, quite satisfactorily. The instructor could have only been advising as he would have had no input on the controls. This would not of been his first landing so again I presume the 'student' must of demonstrated some ability before being sent 'solo'.
The Stalion51 company is a good example of a controlled training enviroment and I know of several pilots who have taken advantage of it, one of which has less than 5 hrs T6 but is still an extreamly competent P51 pilot.
Remember someone died here, in horrible circumstances in a very public way.