I can't imagine going to all that trouble with 35mm. For me, 35mm is for snapshots and machine gunning action photography. Going to all this trouble to make a "perfect" 24x36 neg seems a bit inefficient to me.
I will meter my subject area. I first pick the brightest highlight area and meter it. I then meter my most important shadow area. I do this first so that I know the SBR and I know what I have to work with. Let's say, the SBR (subject brightness range) is six stops difference including the highlight and the shadow. Now, I meter the other important areas of the scene/subject. I do not choose a portion to fall on Zone V. I measure it all. As much as I can. Once I get the readings a picture begins to form in my mind as to where the subject will fall on the exposure scale of the Zone System. My shadows might fall onto I 1/2 or my highlights might wander just above Zone VIII. But this gives me a good working range to go with and a working knowledge of the brilliance of my subject.