A buddy of mine told me about something similar.There was a variant in one of Ralph Eckert's earlier books. He called the game x-ball:
You play 5 ball ghost and keep score.for.you only. Run out, you get +1, of not -1. If you get to +5 twice, you add a ball. You get to -5 twice, you remove a ball.
You can play that for hours and long term have a good tracking of where you are and see improvement.
After break is always ball in hand, all balls stay down. Early 9 doesn't win, I think.
If you want to continue to get the break practice, do you break the 9 balls and remove the higher balls than the one you are currently playing?