I still think it's much more efficient to let your teams vote for 8 or 10 libraries, once or twice a year, send N dollars for every vote over <enough to make it worthwhile to track down donation information and cut a check> and carry over remainders from one vote to the next, so that everything below the cutoff gets some love every couple of intervals.

A lot of people will vote for the obvious ones, a few people will vote for the underdogs and it'll come out in the wash.

That also fights the common complaint here of people gaming the system by splitting up their libraries too much. Sindre, for instance, would get some money for p-limit, p-retry, and maybe p-queue, but not much else for his astounding menagerie of micro-libraries.