Sometimes I write in their scores, but more importantly, THEY write in their scores. It seems to make more sense for them to write what makes sense to them. For example, we might discuss and experiment with a certain passage, and then I say, "Great! Go ahead and write down something to remind you how that's supposed to sound." Often, they come up with something that's different from what I would have written, but it is their own idea, so it sticks! Usually I just say, "mark it in the score." And then they write whatever seems appropriate for them.