Running the latest Webkit nightly now. Looks and acts identical to regular Safari. All my settings and prefs are the same.
It's blazing fast.
Might as well just run Webkit, LOL.
Webkit does not have a user interface, it's only a rendering engine. When you run a Webkit nightly, it will always use the standard Apple Safari user interface. When you install and run a webkit nightly, you are only changing the underlying rendering engine.