Digital BW, The Print

I've tried Steve and Paul's suggestion (though not William's because 
I don't have Vuescan) and here's what I come up with.  There is 
definitely less clipping in the shadows scanning as grayscale 
positive, though the clipping was only slight before with a scan as 
color negative.  There is a very large difference in tonal scale, 
with a PS file that is flat and light and requires a levels 
adjustment before I can even use a curve.  But I's rather do this 
(levels) compression in PS and match it to the image intent than let 
the scanner software arbitrarily do it (I guess they're trying to 
protect the highlights from blocking).  Incidentally, I'm doing the 
reversal in PS with a simple Control-I, but I can only imagine that 
there is some more complex was to do that.

On the "posterization" I was seeing, there is no difference between 
the two techniques.  I'm beginning to think I'm just seeing precisely 
what most people don't like about Tri-X.  The grain distribution is 
uneven and there is some clumping.  Earlier in my career (1960's) I 
was using D-76 (mostly with a changing bag in the bathroom!) and much 
later went to Rodinal (?) or something like that--it seemed to give 
finer, more even grain.  These newer negatives (c. 1980) don't appear 
to "posterize."

And what are the advantages of Vuescan?  I find the Nikon interface 
irritating and awkward, but I've gotten used to it.