I think that your checklist sounds like a great idea. I often feel bogged down by the amount of information I have learned about each student's mathematical knowledge and find difficulty keeping track of it in an easy way. What has worked for me this year is an idea that I got from a teacher in our district Investigations network. It is a t-chart. The heading of the paper is the activity or session that the students are working on. The paper is divided in half, with one half being labeled "What I Heard" and the the other half labeled "What I Saw." Then, I make note of the children that I observed during this activity and what they said or did. I use this when deciding where I need to go with them and, also, to transfer some of what I saw and heard to my grade book. This has been very effective for me and has not required a lot of time.