Welcome QBDAD, nice to meet yet another slab hunter. its a matter of how long the pvc pieces you have are, the condo is going to set on the bottom so if you are at 12 ft then i would use a variety in size, perhaps from 2ft to 7ft which means the condo would provide cover all the way up to less than 5 feet of water. as for the trees, i would try putting a few at different depths, that way you can fish the deep ones in summer, and the more shallow ones in spring and winter. AS FOR WHEN THE FISH WILL COME, with the trees they go through a "souring" state and may take some time depending on how fresh they are, i normally dry mine out through a full summer before i put them in. It could take a little while for the fish to find the trees. AS FOR THE PVC, I have had fish in mine within two weeks, and I have had condos where it took nearly 2 months. It wont hurt to check them though, the worst that could happen is nothin.