I would do the hole/fishing line and tie it to a rock like the other guys said. Prob the easiest way, and looks the best.
I just dropped 3 pieces in my tank 2 weeks ago from the the fish store. 2 wood and 1 root. They look awesome, but are still dumping Tannins (yes I was too lazy to boil it lol).
I am doing water changes and running Carbon in my Magnum 350. Hopefully it will clear up here in a month or so. The fish love it though. Freaking Boston Tea party in there....lol
Just anchor it down and leave it.
I have rocks covering the base of where my driftwood is so you can't see the fishing line. At this point, I don't care if it ever floats....although I wouldn't mind if it did