(I've done this quickly so someone might want to check my maths)
17x14" is 431x355mm.
Crop to 431x287 to get 3x2 aspect
Then 355*36/431 = 29.6mm.
at f/9 that also works out to a 35mm DOF of 29.6mm f/0.75 (I'd be stopping down to at least 355mm f/64 to get a semi-reasonable 29mm f/5.4 in 35mm-equiv)
I'm also interested in G-Clarons for my 12x20 project, but I probably can't afford one (I'll just stick with pinholes for now)