I am no expert, but I believe anyone who is would recommend a chassis if possible. Better for wire management, and better protection of the sound board, and speaker from the vibrations resulting from dueling. Me being the organization freak that I am, I just like the idea of an apparatus designed specifically for that purpose, that (on the rare occasion that it sees the light of day) looks damned cool!
With today's 3-d printing technology where it is, these things are not terribly expensive, and are tailored for the environments for which they are used. That appeals to me on every level.
I will leave it to the aforementioned experts to recommend a specific chassis for what you are doing, but I think that they would agree that if you can, a chassis is the way to go!