Unfortunately, your flashes won't be able to do the job. It's not that the DLites are altogether useless (they're really rather nice units), but the way they work — the way a lot of studio flashes work, and not just at the lower end — means that the flash duration at t 0.1 (the time when at the flash is firing at more than 10% intensity) is as short as it's ever going to get somewhere between half and full power. The lower you bring the power down, the worse it gets. Your spec sheet will show the t 0.5 going up quite a bit as you reduce power, but the t 0.1 goes up even more. It's just not a good motion freezer. (Nor are the AlienBees, Elinchrom BRX, Style and pack-and-head systems, Speedotrons, Bowens, Photoflex, Profotos other than the new B1 Air monolights,... the list goes on and on.)

Elinchrom makes one monolight, the ELC Pro HD (in two power levels) that will work. The Paul C. Buff Einsteins will do the trick at less than half the price. Most Hensels will work. The Profoto B1 Air (the new battery monolight) will work. So will the whole of the Broncolor line (like you wanted to hear that at the prices they charge).

What all of these flashes have in common is that they control flash duration by cutting off the power rather than changing the charge on the capacitor(s) — just like speedlights do (usually using IGBT devices). And that may be your real answer if you aren't going to be trying to freeze fast motion often: it can be a lot cheaper and easier to beg, borrow and/or steal a bunch of speedlights for a single shoot than to invest in a new flash system (especially when there aren't many IGBT studio units at the lower end of the price scale).

You'd probably need to double, triple, or quad up the speedlights to keep the power down and the flash duration short. And if you can narfle enough Nikon (or at least iTTL-compatible) units, you even get the option of using rear curtain sync so any remaining ambient will give you fat-at-the-bottom drops.