For most of the time, no. There are many factors that affect speed and you don't know the speed until you make a test batch with exactly the same material, method and technique.Is it possible to 'set' the speed to a predetermined factor -- meaning can one make an ISO 100 B&W emulsion with any fair degree of acuracy?
If not, why?
Experienced emulsion makers have accumulation of data from an emulsion made with one or two variables shifted within a reasonable range. In this case, it is possible to aim a specific speed a priori. Even so, you typically make a test batch to confirm that the emulsion is exactly what you need.
In reality, pictorial photographic emulsions are a blend or multilayer coating of 3-5 individually prepared emulsions. (In case of color, for each color layer, there are at least 3 emulsions involved.) The speed of the material is again influenced by the blending of the individual emulsions as well, although it is largely determined by the fastest one.