Hi Mike,
I have stacked 2 Aeros, and if you check the sales blurb you will see that this is one of the selling points. There is a shot with six or so stacked!
You have to clear the deck of fittings (again, by design they just slide off). We put pieces of carpet in between the hulls to avoid rubbing.
I can't remember what we did with the second trolley. It probably went on top.