Hey Jason.
For bass... take my advice and use hardwoods. Crappie love cedars, but for bass we have had much greater success on our big hardwood piles. Sycamore limbs work well, for example. We use burlap sacks filled with rocks and sisal rope to sink our piles. The sacks and the rope are both all natural materials and biodegradeable. By the time they biodegrade, your brush will obviously be water logged and set into place. You can get the sacks at feed stores... if you don't see them on the shelf, just ask them if they have any in the back they are willing to sell. Bulk items come into the store in them, and are emptied out... so they are just trash to the feed store, really. Sisal rope is available at the hardware store. Get a little heavier rope than you think you need... dropping a big pile with a heavy sack of rocks puts alot of strain on a rope.
Don't drop them too shallow... I know of a bunch of piles on TR that are entirely too shallow (and worthless) that guys have dropped. Our best night fishing piles on TR are anywhere from 16 to 25 feet deep at normal pool. Be ready to mark your pile on your GPS immediately on the drop for accuracy, before the boat drifts.
Lastly, don't forget to give me the GPS coordinates to your piles!