Lots of people have done the calculations. Poke around the Reddit Spacex forum and NSF forums, lots of discussions there.
> The first goal is to maximize aerodynamic efficiency, which means minimizing frontal surface area.
The fairing is already wider than the first or upper stages, so increasing those stages to the fairing's width would actually improve the aerodynamics.
Can you show me some references to this?
My understanding is that there is a tension between two goals.
The first goal is to maximize aerodynamic efficiency, which means minimizing frontal surface area.
The second goal is to minimize non-fuel weight, which means minimizing the surface area to volume ratio.
It's not obvious to me that the Falcon 9 would be better off shorter and wider.