Just to update on the original topic- I removed the platter and put it in the foam packing material cut out for the platter and then put the top foam on to cover the platter. Done with the platter.
I secured the arm with a bread tie and placed the table/arm into the foam packing material cut out for the table in the box. So the table was sitting in the foam with the arm on, in the bottom of the box. I taped the box so the flaps wouldn't drop onto the arm.
So I ended up with 2 big pieces to pack in the car - the box and the platter in the foam.
That was about it. Worked fine both ways. Thanks for the advice.
Here's a pic of the system in the room. It actually sounded quite nice considering it was comprised of different parts and pieces from 4 of our systems and we just plopped it down and started playing. We had free beer, so lots of friends

