If you insist on an instructor, he could look out of the other door or use the the tail camera.
so how does the instructor intervene if the student gets it wrong? How do you teach stretcher entry to the cabin or even double lift entry to the cabin?
The student can't learn what real winching is like with a wooden cross on the hook and if you just want to practice his voice marshalling you don't need to winch at all
As for the weights - I am just going on what I have been told - perhaps the empty weight of the MFTS aircraft is greater than yours. The Metropolitan police had plenty of plans to use the winch on their 145s but I was told the problem was being safe OEI for training