Something that just occurred to me; when pushing a cannon to an embrasure, you can push it in from the side, and it will automatically point itself toward the correct embrasure and lock into place. You don't need to push every cannon straight toward the embrasure to get it to arm itself.
This might be fairly obvious, but it might catch someone up if they think that's what they need to do all the time.
Anyhow, thanks again for playing! :)