Re reduced power takeoff.
When teaching for the Cpl I always did a reduced power takeoff as a dual exercise. The purpose was to expose the student to how the airplane would feel and what the performance would look like when attempting a high density altitude takeoff. It was also valuable for reinforcing the importance to fly the airplane on speed and perfectly coordinated. The difference between a few knots too fast and the ball 3/4 out of the cage can be as much as a 50 % reduction in climb rate for a low powered airplane and high DA.
I also used the "make the airspeed indicator go to zero" exercise (in the C150/C172) part of my slow flight training. I was amazed at how many students had never been slower than 55 kts and how they thought they were going to die if the stall warning horn came on on flight. Concentrating on what the aircraft felt like at low speeds was a good confidence builder and emphasized the point the airpalne should always be doing what you want it to be doing at any given part of the flight.