Are you sure that you've matched the Quadscan output format
to the 21N input format?
When I hear someone say that they have too much green -
it might be because they are taking a component signal
Y/Pr/Pb and feeding it into an RGB input.
The Y signal would probably be connected to the green input.
However, since Y = Green + Red + Blue; the "Green" signal is
too strong because it is total luminance; not just green.
Since the Quadscan has both RGB and component outputs, and
the 21N has both component and RGB inputs - make sure you
don't have these cross-connected.