[abroerman]

exporting with the DV-NTSC format resulted (even after 6 hours of tweaking) in a file the five times larger than when using the H.264 codec with much, much worse image quality. Will this still get disqualified?

I'll quote a post DLavery made not long ago:

Your animation will NOT be judged if you didn't read the rules and submit it in an acceptable format.

I have been perusing several of the animations that have already been sent to Streamline. Of the 51 animations I looked through, 24 of them - practically half of the entries - use illegal codecs, have improper image size, exceed the file size, or exceed the time limitations. Half of the entries are not in compliance with the submission requirements and are probably going to be disqualified by Autodesk. Based on past practice and what we have heard from Autodesk, they will be absolutely ruthless this year in ensuring compliance with the submission rules.
...
Some otherwise fine animations are going to be completely ignored because someone on the team made a stupid little mistake like using a MPEG-4, animation, Sorensen 3, or H.264 codec instead of the required DV-NTSC codec.