Use ffo = poser.Scene().CurrentFireFlyOptions() to obtain a FireFlyOptionsType object.
You can then use ffo.BucketSize() and ffo.SetBucketSize(n) to get and set the BucketSize respectively.
See the section of the "PoserPython Method Manual" entitled "FireFly Options Methods" for the method names to manipulate other settings.
The values obtained from the FireFlyOptionsType object reflect what's set in the "Manual Settings".