The Kone instructions you appear to have used (for a 4X12) are not for stereo - they are for a series/parallel mono cab. See if you can find a schematic for a marshall mono/stereo cab and pay close attention to the impedances that result from their switching.
Edit: You could wire up each side (ie top right + bottom right also top left and bottom left given you 2 +/- pairs) as in the Kemper 2x12 diagram and then use the outside sockets on the cabinet plate - Ignore the centre socket and switch. If you are hauling a Stereo 4x12 around then who would you need mono?
Be aware:
2 Kones in series = 8 Ohms
2 Kones in parallel = 2 Ohms ... DO NOT DO THIS!
HTH