BR

For a VolumeAnalysis <FWHM>=6 is typical. For a SphericalAnalysis, it is common to apply minimal smoothing (<FWHM>=2) in VolumeSpace and then apply additional smoothing in SphericalSpace using FsFastSphericalSmooth. See EffectsOfSmoothing for a discussion of the consequences of smoothing in both VolumeSpace and SphericalSpace.