Never done it, but observed it.
Like youth soccer, there is a lot of standing around, in line. Coaches everywhere have to ditch the standing in line waiting your turn, that is too much baseball for real coaching.
Don't hire me, make me coach a bunch of junior college kids, I would put them into the racket ball court with their rackets, and have then drill a six hundred times, on each of the major stroke classes, working each for flat, top and bottom spin; against market targets on the wall. This is a three hour practice. What else? Have them pick their favorite top ten player and copy their stokes exactly. Each of the top ten have had detailed stroke analysis videos plastered everywhere.