Attached Link: http://www.keindesign.de/stefan/poser/firefaq.html

There are no one "good" Firefly setting. It depends on the image you are rendering.

Stefan's Firefly FAQ explains what the various settings do.

Note that if you use Minimum Shading Rate to fix noisy hair textures, you have to change the properties setting for the hair (or anything else you want to be affected) as well as the render settings.

And in some situations, you might get better results by using a lower max. texture size. (Rendering a small image with large textures, say.)

I use a little bit of Gaussian to soften dynamic hair.