I agree with most of what you said. I run 17s in front and 18s in back on my personal car, after all. Staggered setup. I actually have 235s on front and 285s on rear right now... understeers like mad. That's temporary though.
And I, like you, am just a joe schmoe who reads stuff online. Hopefully in a couple years I'll be able to say a little more about my credibility, however :)
Would be interesting to talk to those engineers, though.