Hi all. I'm packing up my 1.6 and don't quite recall how they go. Specifically the end of the box styrofoam. It's only think enough to hold 1 speaker in place. I don't think I lost anything, but it's been years, so who knows.
Call Magnepan and ask them to guide you through. They're nice, if they pick up the phone. I seem to remember that one laid somewhat on the other at and angle with a foam spacer. I had others that were shipped mono. I would call them.