I have tried the drills, but I don't like hitting the same shot over and over...as I don't think that it helps in game situations that you don't get more than one crack.
However...If there is a particular shot that you are having trouble with...It does help to hit it 50 times to learn how to make it.
I have recently switched to practicing similar to what I saw Mark Tadd and Tang Hoa doing.....
I witnessed both of them doing the same thing....(especially Mark).....
He would throw out all 9 balls...(literally at one time...I cant do that as I cant get all nine balls in my hand at once)...
He would just run balls until he missed some "off type" shot...He would stop running balls and hit the same shot over and over about 20-50 times...then he would go back and run balls again...find another shot and repeat the process....He then switched to hitting banks only for a while, and then back to just running out...(but he would always stop and hit a shot over and over if he missed)
Tang did the same thing...He was running balls and he missed a (low percentage) long "extreme" cut shot...He stopped running balls and basically spent the next 30-45 minutes just hitting the same long extreme cut shot.....
Lately I have incorporated the same type of practice...I start out with all the balls and just make any available shot for about three racks...Then I switch to 10-ball...I run balls until I find a shot that I either miss, or have trouble getting shape....As I find shots...I will work on that shot unitl I make it consistently...then go back to running balls.
I did not see this being done by Mark or Tang, but I have also started practicing "playing safe" I will start with all 10-balls and practice playing safe no matter if it is the right shot or not...It is just practice getting safe from anywhere no matter how the balls lay...I then will run down some of the balls and practice playing safe with less balls on the table...Some of them are almost impossible to get safe, but I think it dials in your CB controle and opens up your safe "options" during a match....When I do get safe on a shot, I also try and make the hit from being hooked, and look for ways to "kick safe"..
I will then play a few racks of banks only.....(doing the same process of if I miss a bank...I hit the same bank over and over)
After I have done all three...I will rotate, (run outs, safes only, banks only)
It seems to be helping...and it removes some of the boredome of just running racks or doing drills...