A couple things to add to the other answers and some other options:
You mention wetting the sand to make it settle. Think of building a sandcastle. If you put water in bucket full of fine sand, it's won't come out easily. It clumps. If you want to make it flow when wet you really need to basically have a pool or flowing water.
Fine sand, when wet or damp clings together. This brings us to the question of what is under the sand. If you put the sand on top of gravel and then wet it and put the pavers on top, this is exactly what happened to me when I built a patio once, just over a longer period. the wet sand clumps and will hold together on top of the gravel, even with a vibrating compactor. Then when the sand gets really dry, it will start to fall leaving voids.
Another option is stone dust. It packs together more tightly than sand. Otherwise, if you are putting the sand on top of gravel, it will continue to fall through until pretty much every void between the rocks has been filed in. If you don't have a border, it will move out of the sides and you will need to keep filling it in. Don't bother with polymeric sand until you get the settling issue solved..