Digital BW, The Print

Hi all,

Can somebody please help an idiot get his head round this please? 
I've tried mixing my own quad ink set and had some limited success. 
I now would like to try mono printing in a spare 1290 I've precured 
but am not sure the best way to proceed. 

Any thoughts would be appreciated on this or how to make it a 
variable tone inkset.

Thanks again

McGillicuddy