I have a nice piece of driftwood, 23" tall, 25" long, and 14" deep when set up on its base as shown in the first photo. Sits up in 3-4 different positions on its own.
Has a bit of built in buffer on the inside of one of the limbs (barnacles). They can be popped off with a man's thumb or a girl with a screwdriver (not the drink) or they will break down in a few months due to the pH in african tanks.
It is still prety much water logged so it wont take long to submerge and these ocean pieces don't contain many tannins.