I've thought of doing this, but I don't really understand airframes enough to go in blind...a stick kit seems a logical first step...
Not sure what you mean by going in blind. As I said before the main difference between a kit and scratch build is the pre-fabricated parts!!!
Maybe I'm misunderstanding you defination of scratch building?
I define scratch building as building from a set of planes and fabricating your own parts. Since the designer of the plane already knows all about airframes all I got to do is build the model to the planes.
If by scratch building you also mean that you are going to design the plans then yes I would agree with you that understanding basic aerodynamics would be a minimum requirement.