Scott,
In your opinion, does Mother Drill 5 carry over to your game when the cue ball contacts an object ball or when you're doing anything other than just rolling the cue ball? I can do this drill really good, but can't get the feel for the speeds very well when I'm doing anything other than just rolling the cue ball like in the drill.
I'm not Scott, but I did take a lesson from him at one point, and I think I can pretty much answer your question.
There are three elements to speed control:
1) Judging exactly how hard you need to hit a certain cut shot to get your CB where you want
2) Actually hitting the ball exactly that hard
3) Hitting the cut shot exactly the right thickness, since hitting too thin will make you run long and hitting too thick will make you come up short
All three elements are critical; any one is useless without the other two. Mother drill 5 will give you #2 if you practice it well. Stroke mechanics, eye patterns, and alignment all play a part in #3, and there are drills to help with those things too. But as for #1, only a great deal of experience playing a variety of cut shots will teach you to judge exactly how hard you have to hit the CB to get where you need after a given cut. Which is why drills are great for giving you the tools, but you also have to practice playing the game if you want to really get good at playing the game.
-Andrew