I've gotten my bookkeeper working now, huzzah! Highest precision is achieved in less than a season (from lowest), and I know have full insight in my stocks! And with ~3500 prepared meals and ~2500 drinks, I don't think I'll have to worry about my dwarves starving anytime soon!
In other news, the spring melt continues to be a problem, despite me setting the lake and rivers to restricted (max cost) areas, and the paths around it to lowest possible travel cost, my dwarves still seem intent on passing over the lake. Which, especially around 12th of Slate, can be... deadly. Costs me one to three dwarves each year.
This last year I noticed (too late) that it was 9th of Slate, and immediately told my dwarves to burrow inside the compound. No use, it seems, since someone went back out to claim his "personal goods" that he had left somewhere, and passed over the ice just as Armok did his "ice to water in less than two frames"-trick. Interestingly enough, this doesn't just cause the dwarves to drown, it seems to cause them to sink immediately. This particular dwarf was three z-levels down in an instant (the lake is four z-levels deep) and died, as far as I could tell, directly, i.e. not the normal, drawn-out drowning death.
At least this way I can say he didn't die in vain, but rather as an interesting research experiment for !!SCIENCE!!. Might have to repeat the process a couple of years to get reliable data, but that seems to take care of itself at the moment.