Digital BW, The Print

Hi there, new to this group and looking for some advice from your vast
knowledge pool!
I have a 1290 using Mediastreet plug&play dye inks through a CIS and am
pleased with my photographic prints, mostly on matt papers.  I have done a
fair amount of B&W prints (using colour inks) over the last 3 months and
have been generally happy with the results, but the longevity sucks, I have
prints that have faded dramatically after 8wks in a window - how this
corresponds to 'real life' conditions I have no idea, either way, I don't
get a warm feeling.
So, I have decided to give Generations G4 colour pigments a try and have
read good reports of gamut, Dmax and longevity.  BUT - I have no idea how
the performance of these inks will suit me for B&W prints.
I know this methodology is WAY behind the kind of hi-tech solutions you
folks are using but I am not ready / cannot afford to go the quad/hextone
route yet, so this is a real option for my B&Ws.  I guess most people here
have upgraded from colour B&W prints at some point, so does anybody have
any experience on how the prints from this pigment set would compare to the
dyes I have been using or OEM inks when used for B&W prints?

Help appreciated

Steve.