I'm talking about interrupting a practice session by having to write down results, which I'm pretty sure activates the wrong part of the brain for learning. One of the best tennis drills I learned was to get the ball over the net as many times as possible, period. Don't worry about anything else. Just immerse yourself in the idea of hitting the ball high and easy for the other person to do the same (we're talking reasonably good, intermediate players). What happens is you get into a bit of a trance where you are zoned in on the ball and you can start playing around with your timing and body position and various aspects of the swing. Because you are hitting the ball high and easy there is little risk of missing a shot and you get immediate feedback and can keep trying things on each successive shot.
You are correct in that there isn't much record keeping on the Hopkins challenge during the run, only after each rack. If you are playing a game or trying to get a ranking you have to keep score. Remember, my initial comment on all this was that while the drill is interesting and good, it doesn't necessarily translate to other games. I am never going to have to choose my last five balls and hit them in rotation in any other game. It is interesting and fun to try, but I wouldn't spend the time to master that strategy. There are other drills that would be more useful to your game of choice, straight, 9 ball or whatever.
