<<Just found the web site if anyone is interested. I am thinking of giving
it a try to slow seam rust until I decide what to do.>>

Ezra - I tried a similar product - you'll find several in the
"anti-corrosion" section of a marine supply store i.e. West Marine.
They all make about the same claims. I've used one - "BoeShield" -
supposedly developed by Boeing for aircraft use - on my salt-water
fishing tackle for quite some time. It seems to work about as well
as oil does, but it isn't as messy. However, I don't think it'll be
much use on the exterior of the van. I applied another product - I
can't recall the name but is had a bluish color - liberally to the
weld behind the front bumper (water collects there) and to one area
of a slightly rusty body seam. It really didn't do anything at all.
In fact, after a few weeks of driving, it seemed to completely wear
off. I have a feeling it works just fine in protected areas that
might be exposed to dampness and salt air, but it doesn't really seem
to stand up to the extreme exposure to which the exterior of a vehicle
is subjected.

just my 2 cents...

Doug Fitz-Randolph
Yarmouth, ME
'90 Syncro