What a great discussion!  Because my son is a SW, I have frankly never thought about that "fine line" between the two..  I know he is SW because he had the classic crisis at 10 days of age.  Quite scary.  I did want to add a point about what I have "read" from parents and what my doc has done re: dosing.  There have been times that it seemed a need to increase cortef dose, but the doc was concerned about growth.  So, we we upped the florinef a bit and have had good results.  I have heard the same done with SV.

My son is 7 and we have not had any weight problems, sensitivity to heat, problems participating in sports.  He is quite slim, but good muscle tone.  Is very active in soccer, swimming, and baseball.  Especially soccer.  Even is 95*  August heat in the south at soccer camp, I have never noticed the need to hydrate more than other kids.  He does like salty foods, but I do not salt his food any more than the rest of the family.