I am a supervisor/trainer here at Mammoth Mtn. At Mammoth West (Main Lodge) Sports School, we have 10 Sup/trainers, who do probably 95% of the training. We are all PSIA level 3, and most of us are active in the certification process; clinician/examiner. Each of us has a "family" that we do are in charge of training. My "family" is all PSIA Level I, or the Aussie or Kiwi equivalent, and training for level 2. All of our instructors get 1 hour of paid training each day, unless they are booked with privates. Every day, we offer unpaid "day off clinics" from 10:30-12:30, and often from 2-4pm. These are quite popular, and usually really fun. Our exam pass rate is super high. Last year I had 15 people in my family, and 10 of them passed Level II, and three passed Level I, no fails. There are just a few instructors that do not have at least a I, most of the new guys did it last week. Until this year, you had to be at least level II to even work at adult ski school, but now, we are trying to have one big school, not totally seperate adults amd kids schools.
We actually have two "staff trainers" at Mammoth, one at each big lodge, but they are really just supervisors who are former or current PSIA Demonstration Team members. Our "Staff Trainer" is David Manetter, who spent 12 years on the D Team. At Canyon Lodge, Carl Unterkoffler (present D teamer) is the big cheese.
I taught at Mammoth Kids (Woollywood) for 4 seasons, and then became a supervisor. During that time, I mostly skied with high level kids classes, and all sorts of privates. I only taught two adult group lessons during those years, a First Timers class, and a Mammoth Masters class, but I did teach some high level adult pvts, mostly parents of kids in my classes. I came to Mammoth a fairly strong skier, with few bad habits, and passed all my exams by the end of my third season. This is actually fairly common here, we really train hard.
In addition to all of us PSIA guys, we also have Full certs from New Zealand, Australia, Austria, Switzerland, the UK, Etc... A pretty diverse bunch, and really fun.