@Chris Jones: Yes, although "m" is a general-purpose parameter in SPICE and can apply to any device or subcircuit, while "nf" is a parameter specific to bsim MOSFET models (possibly only bsim4?). "nf" has the somewhat oddball definition that when it is used, "w" represents the total device width (sum of widths of all fingers), whereas if you use "m", then "w" represents the width of a single device. There is a patch to ngspice branch pre-master that was made two weeks ago, but I have not checked back in with Holger Vogt to see if there has been any update, or if has been merged into the master branch.