Well...the idea is to change nearly 100% of the water when the tank is cycled (replacing it with conditioned water so all of the bacteria in the tank stays intact) and then add all of your fish. Moving water from the old tank to the new tank really wont do anything as long as the water conditions aren't drastically different. They're going to have to adjust to the differences no matter what...and I doubt that the driftwood would change your water's chemistry instantly.
It might be a good idea to experiment a little with the tank and the gh/ph etc before your cycle is over, just to see how much or how little it takes to adjust it a little when there aren't fish in there. Usually the driftwood will change chemistry a lot in the beginning and then slow down I think (someone correct me if I'm wrong)...but I suppose it always depends on the type of wood too. I am mostly basing that thought on the fact that a lot of driftwood releases coloring into the water for awhile, then with each water change it gets less and less.
