Fujinon W 180 & 8x10

[xkaes]

I think it is clear there was an empiric observation the 180mm WS only fits a Seiko shutter. S = Seiko. See post #14.

The 180mm always came in a #1 shutter, and as mentioned in post #14:

Of the single-coated lenses, those in size 0 shutters (150mm and shorter) are always Seiko. Lenses in size 1 shutters are often found in either Seiko or Copal.

And since W S lenses appeared in Copal shutters from 180mm (#1) up to 360mm (#3), the "S" can't refer to "Seiko".