Cheers,
Steve
AS10 = XF20 (FS36270)
AS27 = XF24 (FS36118)
Tamiya don't really do equivalents to medium grey or light ghost grey other
than the AS range, which to my eyes are too bluish anyway. Try Vallejo Model
Air 71050 or Lifecolor UA026 for light ghost grey FS36375, and Lifecolor
UA034 light grey for medium grey FS36251. Then again, now you're armed with
the FS numbers you need, have a look at
http://ipmsstockholm.org/colorcharts/stuff_eng_colorcharts_fs.htm
and see what there is on there.
Hope this helps.