I used to fly an average of 80 hours a month and in the summertime over 100 hours. I worked at a big flight school with about 70 instructors and over 500 students. But flying that much kills your social life and you get burned out pretty quick.
Each instructor had 12 to 13 students, who had to fly a minimum of 8 hours a month each. if you were a ground instructor or a CFI instructor you had 8 students.
As far as multi time goes, we had contracts with Chinese airlines, which included between 45 and 60 hours of multi time per student.