Assessment: tiny notes in tiny boxes

Over the course of a school year, I see approximately 700 students in grades k-5 (once a week for either 1 or 2 terms).

My current system for assessment gauges how they do on the work I give them each week. If they do their job, they get a check; If they do it really well and help others, they get a check plus; if they do it beyond my wildest dreams, they get a star; if they sort of do it, but miss some point, they get a check minus; if they totally don't do it, they get an x--so it's sort of an assessment of the whole set of skills they use that day. I also use other codes like ot for off-task, fd for trouble following directions; h if they need extra help; hk for uses home keys, p for printed, a for absent, or b for major behavior problems. (I also keep separate sheets on the 4th grade bloggers, and 5th grade movie-makers, for whom there's a lot more information to track.)

Each mark or code goes in a box a little smaller than my pinkie nail--to accommodate a class of 32 students for 12 weeks on one sheet which also acts as a seating chart. It's hard to fit much information in a box that tiny, and I have more benchmarks than I have boxes (a possible sign that I am teaching too many things in the time I have, but I'm not prepared to cut back). I will sometimes make additional tiny notes that I need to work on a particular skill or concept with a particular kid, but not consistently or comprehensively, so the system has its flaws in terms of assessment driving teaching in a concrete way.

The only alternatives I see would be either:
a) Design a new sheet with fewer, bigger boxes for more notes per kid per week (which would also require that I devote more time to writing those notes each week, and consequently less time to teaching), or
b) Determine 5-10 concrete benchmarks per term for each grade and assess just for that (and effort and behavior) rather than for how they do generally on each particular day's tasks. This is closer to what other specialty teachers in my school do--most assess based on 4-5 benchmarks--but I have been resistant to condensing or reducing my goals that way. Given that my current system isn't giving me all the information I need, it may be time to reconsider and redesign the system.

Action items:
1) See if other techie teachers talk about this online
2) See if I can possibly boil down my goals to 5-10 benchmarks per grade per term
3) Take nap