Where is this sacred six panel arrangement described as a must-have?

Where does it say that I can't have any other arrangement but the traditional six pack?

I'm not arguing whether or not the six pack is the most optimal from a human factors standpoint. I'm trying to find an FAA citation for that assertion.

To my knowledge there is no FAA citation - I am interpolating from the
conversation I had that my FSDO would not approve installing a
non-certified part where a certified part is expected, but would be ok
with the installation of a non certified part which is completely
auxilliary to the aircraft (such as a CD player or a backup AI).

The line is fuzzy. I would expect the "six pack" to be on the far side
of the line, and I am using "six pack" in a slightly more metaphorical
sense actually.

Jose
--
The price of freedom is... well... freedom.
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