All of this is over thinking the problem. Here's why. Concrete retains moisture, put a block of concrete in a bucket of water with half the piece in the water the other half above, watch the water get sucked up into the dry concrete. The pole is in the concrete and will be wet when the concrete is wet. CCA treated poles last as long as creosoted poles. You could place the pole in the ground, surround it with pieces of broken brick and or rock and bash the stone/bricks until the pole is firmly planted and then fill with soil all the while bashing the soil with a 10 pound hammer, this is what I have done, works well saves the concrete. But the kids will be playing on the poles so use concrete and get the strength. I've seen people wrap the pole in plastic, huge mistake, the concrete will dry as will the pole, when it rains it gets wet. Anyway its not like the pole is in a pool of water it's just damp. Put stones at the bottom, the water will dry out of the soil anyway, check how dry the soil is in the bottom of the hole when you dig the hole. Unless you live in a swamp the hole will be dry. You will not get away from the pole getting wet if it's outdoors. Don't worry, the pole will be there long after the kids have left home, it's how wooden decks are built.
