unyquity
Great questions - sadly I don't have all my data together.
However, I am working rapidly on a "major dangers of Vitamin C" paper, that may take a week or more.
In the meantime, read this: Ascorbic Acid Is Not Vitamin C
(which includes FAR more than just Vitamin C information)
http://www.thedoctorwithin.com/vitaminC/Ascorbic-Acid-Is-Not-Vitamin-C.php
The best source of TRUE Vitamin C is Acerola Cherry powder...NOT the extract or some 4:1/8:1 blend of that and something else. The true ground Acerola Cherry.
This can be found at Pacific Botanicals...it's great to add to Superfood smoothies :)
Blessings -
Unyquity