I have noticed that the size of the drops do not seem to be very consistant between droppers. But about 15 drops equals a ml, I believe. So if you can accurately measure out ml's, or even better .5ml, then do away with the droppers.
How many drops do you need per print? Use water and put that many drops in a measuring cylinder. If there is not enough solution to accurately measure out by the ml, you might be able to mix up enough for two or three prints at a time, then after mixing, divide it up.