is to have A/P ON & FD OFF. The FD will always be centred with automatics in CMD.
It is not permitted and it is not a good idea to do so because when the AP misbehaves it may not be easy to detect. Pilots definitely should be allowed to practice manual flying when the circumstances are not hostile. But you don't develop deviations from automation SOPs especially with FBW. Take the case of SFO B777. The crew kept one side FD on without even knowing that it will not allow the ATHR to transition to the required mode. Had they not done so with all things being equal they wouldn't have crashed. MPL training in my opinion is a better way for low time pilots. As long as some talent is there and in the hands of knowledgeable instructor they should be able to give good account of themselves. There is ample time to mould them according to their strengths and weaknesses. In normal type rating trainee needs to be at a certain skill level to start with otherwise it is a struggle.