I've never been too patient with driftwood, so I learned to screw to the UGF (in a new setup, of course) or simple tie it to a large piece of glass. Glass is heavy ans will almost always sink the wood to the bottom. After 2-3 weeks, I remove the wood, un tie the glass piece and ti will sink right away.
BTW, I will hijack this thread: what's tha difference about driftwood and bogwood?