Digital BW, The Print

Thanks from the few of you who answerd my question.
However, none of the replies mentioned the reason for the number they
quote as the minimum number black inks for fine art B&W.
I made a couple of considerations in the meantime:
1) The gray shades where the print start to look poor ar the lightest.
That's where the dots from the print start to become visible.
I have never seen such dots in the mid or dark tones
2) From a recent post from Clayton Jones
(http://groups.yahoo.com/group/DigitalBlackandWhiteThePrint/messages/78918?threaded=1&m=e&var=1&tidx=1)
it appears that the gray ink used by far the most is LLK. This means
that LLK has to cover a larger range of tones by itself, when compared
with the other gray inks. Therefore, it might need some "help" from
another gray shade.

The above considerations would suggest that the minimum number of gray
shade for best results is, infact, 4 with a LLLK supplementing Epson's
LLK in the highlights.

I would like to know what you think about the above.
Thanks. Cheers,
   Daniela