Digital BW, The Print

I am in the UK and I currently have an Epson R1800 and an HP B9180. I 
am short of space and want to get rid of the B9180 and make the R1800 
work harder for its keep. I would like to use it for color IMK and PK 
papers) and BW (again MK and PK papers) by switching inks every now 
and again (not too often) between MIS's R1800 color set and an MIS BW 
set. 

So my questions are:
1. Is there a BW inkset that is compatible with the MIS color R1800 
inks and do not react with them to clog the heads?
2. With (1) above in mind, can someone please recommend an ink set 
for this printer that will work with papers requiring photo black as 
well as with matt papers? I have used QTR in the past with a 2100 so 
am happy with that workflow and I do have a Colorvision spectro to 
linearise and undertake any other requisite measurements. 
2. What is the best way to deliver the inks - use the MIS refill kit 
to refill the OEM Epson cartridges or get some refillable cartridges 
off Ebay? If the latter, is there a vendor that folk here have 
experience with and can recommend? I would prefer not to go down the 
CIS route.
3. I know this is a BW group but has anyone here had experience with 
the MIS R1800 color inks? In particular I want to get rid of the 
bronzing and metmerism of the Epson OEM inks and MIS claim that their 
inks are much better in these two regards but at the expense of less 
gloss than the OEM inks. Can anyone who has used MIS R1800 color inks 
collaborate this claim (or refute it for that matter!)?

All and any assistance very much appreciated!

regards

Alistair Owens