red cast in high backlight negatives, Duoscan + FotoLook

I have been working with a Duoscan HiD for a couple months and
getting generally good results with color transparencies and
negatives (haven't ever even tried it in reflective mode.)
The problem is that it's magic, and therefore naturally does
not work reliably. My worst problem is color negatives taken
outdoors with a cloudy sky. Obviously a big problem since
I am in Seattle, where this is the normal condition. In these
cases, the clouds become red or magenta, like a weird sunset.

The most effective strategy I've found so far is to pull the
"backlight" balance back a good ways into the midtones, which
turns the sky mostly white and blows out a good deal of the
rest of the image, and pull the white point back very near it
to clip off the rest of the red cast. This pretty much ruins
the image, but at least there's no cast.

Curve correction hasn't been very helpful at all. The
neutral color adjustment will remove the red but leaves the
image generally out of balance in the opposite direction
(which I guess means that the problem isn't strictly a color
cast.)

Next (I just thought of this while typing), I'll try the
gradation control to see if I can recover some of the
remaining contrast range in the image after clipping the
bright half off with the range control. This is another
issue I have, though, it seems to be hard to apply various
controls to the preview and then have all of them come out
in the final scan as it does in the preview. I found some
mention of this as a defect in FotoLook that could be addressed
by running in transparency mode and switching to negative at
the right moment, but the instructions were not in very good
English and I'm not sure I followed (doesn't seem to work.)

The negatives may be overexposed, that happens, but the one
I'm wrestling with now looks fine to me. Kodak 160NC,
which by reputation should be easy to scan, and I have the
same problem with Agfa Optima 100, Fuji NPC 160. I have
Vuescan for OS X, and it will drive my scanner, but not as
smoothly and the results don't seem any better.

Anyway, sorry for the lengthy post. Anyone learn to solve
this for your own images? Understand at all what the backlight
range adjustment is doing? Know how to apply multiple controls
to a scan preview?

Thanks!
Donn Cave, donn@drizzle.com