Digital BW, The Print

I'm in the process of getting a R270 to do BO with Eboni. Two questions:

I want to build a CIS unit using a damper. Here in South Africa I can 
get Epson dampers for a 3000 or a 7600/9600. Which should I use?

I only want to use one position and leave the others unused. (I'll put 
the chips a la Paul's suggested method). Can I leave the other jets 
completely open  or should I put dampers in there with say a 
water/glycerine mix?