When I worked for Ilford Limited in the 1970s, we would occasionally commission a well-known photographer to shoot pix for our campaigns. In the course of this work I met MB-M a couple of times. I did not see him operating a camera, by the 1970s he was shooting rollfilm. As he was a Brit, he should have used a Gandolfi for any 8x10" work!
Do you know which sort of focal length of lens he would have chosen for the majority of his portraits?