A practice tree can be beneficial. I have one of the Biondo full size units. Set it up in the shop in front of my car. Made a jumper harness to allow me to use the switch in the car instead of the little button that the came with the practice tree. That way you're using the same switch, hand position, etc. as when you are racing. Also allows you to experiment with different switches, hand positions or what ever. And you verify switch function.

We had kids coming out of Juniors jumping right into .90 cars. A kid with 8 or 9 years experience and 17 year old, video game tuned up hand-eye coordination could embarrass an old man if he wasn't on his game.