Digital BW, The Print

I've recently got my new Epson 1280 up and running using the MIS VM 
ink set (with the MIS continuous feed system) and the workflow and 
curves developed by Paul Rourk et al.  The results on EAM are 
stunning. I have two questions however.

First, I've just started experimenting with Museo.  Although I like 
the weight and feel of the paper, my first several prints are showing 
some sloppiness in the "mid-shadows" (not the darkest blacks) that 
looks like mottling or "poserization." It appears that the Museo may 
be more absorbant than the EAM and is soaking too much ink in these 
areas.  Any suggestions for dealing with this?  I'm wondering whether 
different paper settings in the driver might help.

Second, I see that there are three different "neutral" curves in the 
files.  What is the difference among these?

Thanks for any help.