When printing a dithered or stochastic dot, a couple of things...
1. Try some tests. Outputs expressed in DPI don't translate to halftone screens. You need to be concerned with the size of the dot as it is always the same. Pick the smallest dot you can expose without losing detail. If it is too small, it will close in on the light areas, and blob on the dark where there is a concentration.
2. Contrary to myth, a random dot will produce moire. Avoid evenly divisable DPI to mesh count situations. Example 100 DPI on a 200 mesh screen. 150 on 300 mesh. Choose odd numbers...I used 157 DPI for a bunch of prints I did, it worked great on 280 mesh but had banding and moire on 305 (157 although not exactly divisable to 305 was close enough to cause probs)
3. When possible, use quality film posi's...like vataugh sez, high rez output will give the edge of the dot definition. If you use cheap film with lower rez, the dot lacks both definition and opacitiy. Output film from a 2400 dpi image setter is going to develop and print way better than some vellum from kinkos.
4. Sharp and nick-free squeegee, high mesh count, and quality photostencil material will give you your best shot at a nice looking print.