I guess that the difference is that I would want to say that the object of the human willing of the incarnate Word is still the object of the divine will of the incarnate Word. The mode of willing may be different, but it is the same. There is a unity of will so that there is only one will, even if the human faculty of willing is preserved in its integrity.
When our Lord willed to do anything I think we would want to say that it was the incarnate Word who willed, humanly and divinely, but it was the same will otherwise our Lord is schizophrenic, and even a duality of subjects. When our Lord willed to eat, it was still the incarnate Word who willed to eat according to his humanity. There is no time at which the humanity wills independently and becomes its own subject. Therefore just as to touch the body of Christ is to touch the Word of God incarnate, so the human will of Christ is the will of the Word of God incarnate, and everything which the human will is moved to will by the divine will is in perfect and complete unity with the divine will. Even in the matter of eating, drinking, going here or there, saying this or that.
The Fathers teach us that when we say that 'this is not the incarnate Word it is the humanity' then we are setting the humanity up as a second subject in whom the Word acts. We cannot say that the incarnate Word wills at some times in his humanity and at other times the humanity wills on its own for itself. What we can say is that the incarnate Word wills according to his humanity in his own humanity in a divine manner. The cannot be two objects of willing, surely, otherwise the humanity wills other than the divinity and is a separate subject. And if there are two objects of willing which happily co-incide then that is no more than Theodore taught and we have essentially a man who is filled with the Word and not a man who IS the Word incarnate.
Who says, 'Come, let us go to Lazarus'? Is it the humanity? Or is it the incarnate Word in his humanity in perfect unity with his divinity? Who says, 'Not my will but yours be done'? If it is the humanity alone then a mere man has died to save us, but if it is the Word of God incarnate, moved by human blameless passions of dread, then we see again that the human willing has the same object as the divine will.
When Christ wills to eat it is surely the divine and human wills together which move him. And there is also a need to distinguish between a variety of wills - which is again why I find talk of two wills not entirely convincing. As humans we surely have an animal faculty of willing and desiring according to certain physiological needs, and we say 'I need something to eat'. But we also have a psychological faculty of willing which when properly ordered wills and desires even contrary to the physiological. I may say 'I need something to eat', but some other faculty of will within me might say, 'but I must finish studying this chapter', even while my stomach keeps saying I need to eat. And we have a spiritual faculty of willing which when properly ordered should take precedence over both the physiological and psychological will. This allows us to say, 'I am hungry and my body desires to eat but I will not to eat, and my mind is restless and desires satisfaction, but I will not turn to mental pleasures, I will pray and will to turn myself towards God'.
When the body of our Lord made some passionless movement of hunger it does not seem to me that this is the same willing as when he says 'Not my will but yours be done'. It seems to me to add confusion to insist that the faculty of will is dual since the human process of willing seems much more complex than that. When we speak of one will there is no confusion, because we are always speaking of a unity of will with a diversity of modes of willing.
The 'instinctive' will of Christ is surely human, but nevertheless it is the 'instinctive' will of the incarnate Word of God. The 'deliberative' will, that higher will which in a man should govern the 'instinctive' will, is surely also human, but is not merely a natural impulse, it is the seat of the person, it is the place where person and flesh meet. When *I* will to do something deliberative it is more than saying *my humanity* wills to do something. There is something personal about my willing which is expressed in my humanity but is not a mere reflex action. The *I* who wills in Christ is the Word of God, always and uniquely. Otherwise there is some other subject. The inner motions of the instinctive will are blamelessly present in the humanity of Christ acting upwards as it were, seeking to be noticed, but the deliberative will (I am just using these terms to distinguish two ways in which will should be surely understood) is not the motion of flesh, but the activity of the person in his own humanity. This is not to deny that the deliberative will does not use some human faculty of willing, but 'to will' is more than a mere faculty, it is an action and requires an agent and an object. In Christ the action and agent and object are always that of the Word of God incarnate.
I will not ramble on, but do please respond so that we can come closer to understanding if not agreement.