FarsideThe fine nib of Japanese pens are like Extra Fine nibs from European manufacturers. I would recommend you getting a medium nib which will "feel" like a fine nib :)
FarsideTake a look on the Goulet Pens website for their nib comparison tool, Nib Nook.
http://www.gouletpens.com/Nib_Nook_s/1114.htm
Just choose the Pilot VP and you can see all the line thicknesses of the nib sizes.