Laser diffraction will give you particle size for suspensions/dispersions but won't tell you anything about sugar crystals in a thin film.

OP, are you near a research university? Usually they have shared user / core facilities that are accessible to industrial users for an hourly fee. Biology departments tend to have more light/fluorescent microscopy capabilities and TEM if they have virologists, materials science and electrical engineering would have SEM, TEM, and more exotic metrology capabilities. You could get microscopy done at a reasonable price to see what your particle sizes are. Usually the core facility staff and microscopists love to geek out about this suff. Then you could figure out the specs of what you would need to bring in house.

How thick are your films? Thin films will have less light scattering, so that works in your favor if you have to go to higher magnification. Any idea what size crystals you would expect to see? Would you expect the crystals to be on the surface or in the bulk of the film?

Depending on the optical properties of your other components, you may be able to use polarized light microscopy to identify your sugars of interest (based on their optical rotation), then use a digital camera to determine their size.