I decided to do the last machine overnight, so started it and went to bed. This morning it was all done - very smooth. I looked at my data usage. For the first (old) machine it downloaded something over 2gb. Similar for the second on the VM. The third downloaded about 1.4gb. So maybe there was a bit of peer-to-peer, but not as much as I would have liked. The numbers are very approximate as Actrix doesn't present the data in a very helpful way.