If anyone is interested, this is what I'm using for my GF4:
HKR,, NV25_Modes_Delta, %REG_SZ%, "S 640,480,-32,-85-;640,480,-16,-85-;800,600,-32,-85-;800,600,-16,-85-;1024,768,-32,-85-;1024,768,-16,-85-;1152,864,-32,-85-;1152,864,-16,-85-;1600,900,-16,120;1600,900,32,100-;1600,1024,-16,120;1600,1024,32,100-;1600,1200,-16,120;1600,1200,32,100-;1920,1080,-16,120;1920,1080,32,85-;1920,1200,-16,100-;1920,1200,32,72-;1920,1440,-16,85-;1920,1440,32,70-;2048,1536,-16,70-;2048,1536,32,-"