They had them ready to be loaded when i arrived. And loaded them easily.
While the sides are smooth and fit fairly tight, there will always be some space between the pavers. I believe it would still be a good idea to use the polymer sand.
I would not, the concrete they are made of would loose its water content and the stones would crumble
Since pallets may vary in size, it would be best if you called or visited your store for specific measurements.
They come on pallets that are 36 inches x 48 inches from the manufacture the the open end on the 48 inch side of the pallet.
I have used them under an outdoor chiminea without problems.