Regarding 3dl --
The lore I've been fed is that Mitch Bogdonowicz formerly of Kodak
wrote (invented? burped?) the 3dl "specification" when he was at Kodak
as a quick and dirty solution of 3D LUT ASCII serialization.
Various interpretations have since been adopted (supported?) by
Arri, Autodesk, Assimilate and others.
Yes, the initial 1D monochrome shaper array is in some cases in a
different bit depth from the 3D rgb array. What's more, various
applications choke if the header comment fields (those preceded with
a"#") are not 'just so' (eg. truelight's tl-utils).
I guess the point is that there isn't just one spec for it. Maybe the
way to deal with 3dl is to treat different interpretations as
ugly -r- us.