I was given a suggestion the other day I am going to try on my next show: Copy the script and put it into a looseleaf notebook with plastic page protectors (they would have to be the smooth shiny ones--usually cheaper) or one of those "Magnetic" photo albums with the plastic page covers. Then, using dry erase markers, simply highlight or underline the appropriate line and use a simple letter code (d for dropped, p for paraphrased, j for jumped, etc.) to indicate the problem. The actors are then responsible for looking at the "notes" script to see their notes. I'm thinking of using post-its with the actors/characters name on them to flag the pages so they don't have to go through page, by page. At the next reheasal, just erase mistakes they don't make, add new ones and leave repeated ones. I think this will work with a small cast, not sure about a larger one. If the cast were small enough, you could use a different color marker for each one. Has anyone ever tried this before?
I should point out that I am a volunteer stage manager in a small community theatre, and am required to be on book and do line notes, a nearly impossible task, no matter how good you are at multitasking. I am currently jotting notes in pencil in my script and then transcribing them, which means actors don't usually get notes until the next rehearsal.