So you want to compare the "as is" and "possible" model.
Well, you want a Ti version of the new grand prix and are disappointed (I assume) that there is not a version. It's just natural for Audemars to build as many Carbon Forged models as they can. They invested heavily in this technology and all these recent models are innovative and ahead of the other houses. Why wouldn't they want to showcase such an advance in modern watch making? For me the new grand prix carbon is flat out gorgeous. The design....yes...but the mixing of materials is what gets me and you can really see the connection to formula 1.
In your scenario there are no winners. All those pieces are great in their own way. Are they hard or easy to obtain? If you have deep pockets any of those are easy to obtain, it's at what price are you willing to pay.
The Grand Prix in carbon will sell out. If they made the Grand Prix in any metal it would sell out. It's just the nature of Audemars and the limiteds (some of course do not do as well as others) they pump out. But I am certain the GP would; not due to the materials but solely on the design.
I am interested to know what your "truth" is as well.