Digital BW, The Print

In the search of a solution to set a single 4800 with a set of PK inks 
and another one with MK inks, I've found on MIS some empty refillable 
carts that can fit any position 
http://www.inksupply.com/funnelfill.cfm

This would eventually provide the ability to have MK with piezotones 
(probably some shades of K7) and aside the OEM PK K3 or MIS UT-FSN (I 
don't like/need toning). 

Now given the combinations :
- 3 K3 + 5 K7
- 4 MIS UT-FSN with PK + 4 K7

has anyone a recommendation/opinion ?
I often hear Eboni is a first class ink, can I expect good results 
(e.g. similar to piezo for mat) with MIS UT-FSN PK on glossy media or 
should I stay with OEM PK K3. 

Besides, any opinion/feedback on these carts ?

Sorry, if some of you feel this is the kind of "please help me 
choosing" post that can be annoying. I'm just looking for some feedback.

Thanks.

Olivier