Nature's blends usually know best for the body.

This information is not correct. its most often heard from
supplement-manufacturers who want to sell their berry-extracts. Ascorbic
acid alone is routinely used to cure scurvey for years, there is not a doubt
that it is a vitamin (which is, per definition, something "vital").

Vitamin C has not all to many dangers as long as its taken in somewhat
reasonable ammounts..
diarrhea is associated with overdoses;
forming of renal stones (oxalate stones) is in discussion as well.
Generally vitamin C is not much of a risk when it comes to overdosing due to
good water soluability.

It does not work wonders, however it does have a broad palette of functions
from stabilizing prolylhydroxylases (in connective tissue, in the hypoxia
inducible factor pathway etc), stabilizing tetrahydrobiopterin in the NOS
signaling pathway and acting as an antioxidant and a regenerator for
tocopherol. This does not mean that taking huge ammounts of it will do all
these things better.. most ascorbic acid above a certain level in a megadose
is simply excreted.

its like when people are building a house..
it won't be finished faster just because you supply the tenfold ammount of
working material needed.

Vitamin C is a group of chemical substances with vitamin c activity.
Those are:
Dehydroascorbic acid, L-ascorbic acid, D-ascorbic acid.

L-ascorbic acid is the one we refer to usually when saying "ascorbic acid"
or "vitamin C" in a clinical context, it has the strongest bioactivity.
The enantiomer with very small vitamin C bioactivity is D-ascorbic acid-
maybe thats what they meant.
Dehydroascorbic acid (DHA) is a metabolite of ascorbic acid decomposition
with smaller bioactivity than ascorbic acid and way shorter half-life (gets
oxidized quickly).
(D and L nomenclature is old nomenclature and almost exclusively used for
sugar chemistry- R and S nomenclature should be used generally)

With right spin and left spin they probably meant the optical activity (the
rotation of polarized light caused by interaction with the molecules).

In chemical terminology they are written with (+) or "d" (notice: no caps)
for right spin or clockwise spin and (-) or "l" for left spin or
counterclockwise spin of polarized light passing through the molecules.
L(+)ascorbic acid is "L-ascorbic acid", so the biologically active form of
ascorbic acid spins polarized light clockwise (right). The other form is the
D(-)ascorbic acid and spins light left.

You should find the above information (and more on it) in any textbook on
organic chemistry and in some biochemistry textbooks as well.

have you visited http://www.vitamincfoundation.org ?

try to find out how much vitamin c is produced daily by animals, this
is the sort of quantity that you will need to improve health.  You will
be surprised at the amount of vitamin c that our organs need to
function properly, especially adrenals, pituitary,brain, eyes, thyroid
and liver.