neg flatness doesn't matter a lot with pinhole since everything is as sharp as it's gonna get, but better flatness does prevent a bit of distortion, but it's not much of a problem either.

My 2000 is not the deluxe version and I like it fine, but I did get the deluxe version of the 35mm one and i like it fine too ... the cable release makes exposures a bit smoother, but since ur using it on a tripod, and long exposures only have a bit of vibration when you slide the shutter, not during the exposure, this also isn't really important.

but, yes, the 25mm pertains to the 6 by 6 format, think of a rectilinear 25mm superwide on a hasselblad, that's what ur getting with this. The Zeroimage pinhole is laser drilled and very precise.