I don't see how it would work? How does it know that you want less boost at low throttle input? It seems like it would just be trying to close the vanes all the way with that set up, and then open them when it sees boost. This will generate very high exhaust manifold pressures and deliver poor fuel economy. It would also be bad if something goes wrong in the system - ideally you want the turbo to default to 'vanes open' if there is no input of any sort, as you can easily overspeed and blow your turbo if they are closed all the way.
While I've been testing my VNT it's really quite apparent just how restrictive closed vanes can be. Coasting along in gear with your foot off the pedal and cycling the vanes causes a noticeable impact. As in close the vanes, the car slows down more (more drag), open them and it moves more freely since now the engine can pump air out of itself again more freely.