I realize this is an older thread, but I would be concerned about the brittleness of these screws. Similar to the concern about using drywall screws for wooden structure, they (dry wall screws) are brittle. In order to drive easily they are thin, so they must have a relatively high yield strength. Er go they are likely to be more brittle. This is fine in a relatively static environment, such as a wooden or steel house stud wall, but might result in issues on a more "dynamically loaded" trailer floor or wall.
Just saying, what is the intended application for this type of scew, and is that comparable to our end uses?
Might be good in the long run, but good to double check.