Another option is to use a developer that claims to be a fine grain developer. These developers sometimes make this claim with very little testing. Please test these developers. Some developers that are true fine grain developers, physically eat away the processing silver to reduce its size. Generally this sacrifices sharpness, but if grain size is the only issue, these may work well.
Grain size is a complicated issue.
There are many attainable options, but grain size can be interwoven with sharpness. Look not only at the grain, but also at the over all image characteristics when you are pursuing fine grain. There are many exotic ways to control and reduce grain. Sometimes these ways are needed, but sometimes a simple answer is the best. Our developer section has some fine grain formula's in it.