Mainly what I do to keep testing simulation-time to a minimum, is to just use a lower amount of particles for testing, then at rendertime, increase the rate to taste.
I believe, although I've never used it, that there is somethin called, "Dynamic Layers" that might be of help here?
Check the docs to see if it exsists, and what it does.
Sorry I couldn't be of more help
Israel "Izzy" Long
Motion and Title Design for Broadcast-Film-DS