The inspirational speaker Zig Ziglar said, “Don’t become a wandering generality. Be a meaningful specific.” The same is true in rehearsal. If you want to improve your rehearsal technique, a big part of the job is to replace generalities with specifics.
We’re going flat. The basses are not making it back up to do on the line sol-ti-do.
We’re rushing. In measure 9, we’re pushing towards the downbeat.
We’re dragging. At the end of every other phrase, we’re adding a microbeat to our breaths.
Step one is to improve your analysis and offer specific solutions to specific problems. Step two is to train your singers to be curious about root causes, and learn how to analyze and solve the problems themselves.