Digital BW, The Print

Hello List!

I would like to know if someone could explain the difference of 
the BW prints made with Epson 1160 4-color and Epson 1290 
six-color printers. I have tried MIS VM-inks at my 1290 and like 
the smooth print almost without any visible dots.
I am planning to buy the MIS FS (or FS-N) inks for my Epson 
1160. Will the print of 1160 be just as smooth if correct 
calibrated, and without visible dots, or would it be better to use 
the 1290 with a six-color FS(N) inkset too?

Bjorn