See my version of playing the ghost here, and more discussion at:
https://forums.azbilliards.com/threads/variations-on-playing-the-ghost.590833/
My version trains the break as well as the run. I have given it the name "modified pro". Here is my version:
1. Breaking, if one makes a ball, no ball in hand. A true break and run attempt begins when one or more balls are made on the break, with the cue ball not moving from the spot where rests after the break shot where one or more ball is made. If one successfully completes a break and run, 2 points for the shooter. If after one breaks and makes a ball, if one is stuck behind balls or there are clusters on the table, there is no ball in hand, in that way, no mercy. In my version, one would need to learn how to execute a good break, make a ball, get a good spread, and get a good shot on the next ball in sequence. If after the break and a ball is made a cluster exists, one is jumping or kicking.
2. Breaking, if one does not make a ball, one can take ball in hand. If one runs out all 9 balls, one gets 1 point.
3. No early nines. If a nine is intentionally made, it is spotted at the foot spot, but spotting the 9 should not in itself create a cluster. If one or more balls is already located at the foot spot, the 9 is spotted at the first place below them to give the player a neutral chance of making the run work. Not easy, not overly difficult positioning of the 9 below the ball(s) that are already on the foot spot.
4. No slop. A ball must be made intentionally to keep shooting. If a ball is made intentionally and legally, and a second ball slops in, that is fine, the second slopped ball can stay down. However, if after the break the first ball is blocked by one or more obstructing balls, slop is allowed when kicking or jumping at the first object ball in sequence.
5. A scratch on the break is 2 points for the ghost.
6. Any miss during a run, whether a true break and run attempt or a ball in hand 9 ball run attempt, is one point for the ghost and the game is over.
My version is for people who are inclined to put in work to earn something. Its also designed for people that want to better be able to "run a table". Progress can equal achievement. If one gets 1 point this week, then one can say "what do I need to work on to do better". Then a month later, or whenever later, one can get 3, then 5, then even beat this ghost.