I appreciate your reply. The question then arises: Who among the current F1 Drivers is known or thought to be able to contribute in this way?
I very much doubt that a driver can or does contribute a great deal to the basic design of a car. Things like wheelbase are the domain of engineers and if the driver isn't also an engineer he isn't going to know more than his engineers about those things. He can, of course, suggest things that he has learned from his engineers in previous teams but he's unlikely to be suggesting anything his current engineers don't already know. The key thing for the driver is to give the kind of feedback that enables the engineers to set the car up to suit his driving style.
Eminently possible, if the car is setup with a certain mechanical balance that is different than the aero balance. The important iota of information to the engineer is that this transition happens between T3 and T4. Thus he can go back and see what speed range was traversed and then he knows something about how to change the setup in the wings (or mechanicals).
It appears to me that it is a bit of a reach for a race car driver to actually have a part in "developing a car". So I find that when posters in the F1 forum bandy about the term and say a certain driver is not good at "developing a car", it amounts to mostly hot air.