Digital BW, The Print

Hello,

I'm new to quadtones technique, and I would know what is the best mode
to use in order to print with my Epson 780 model (6 colors).

I use Photoshop 3 and quadtones from Lyson (Quadblack neutral).

I can use RGB or CMYK in the Epson driver, but it's quite disturbing
to use RGB mode for greyscale image, hoping that the automatic
conversion facility of the printer can achieve the best assignment of
the 6 greys inks.

So, I would like to know if I must stay in RGB, perhaps with some CMYK
adjustment or if I have to go through real CMYK process.

If someone has some fine transfer functions for Lyson inks, I would
appreciate to get them.

Thank you, a french newbie !

Pierre-François Bonnefoi.