Digital BW, The Print

I am using CIS from InkJet Mall in Epson 1280.  I have been 
using PiezoTone Selenium Inks for a few weeks and love their tonality 
and have not as yet seen the fading and warming talked about in this 
group.  Yet needless to say I am very concerned about this after 
reading the recent messages.  My questions concern how to switch from 
the PiezoTone Selenium Black inks to the MIS FS Black.     
     If I clamp the tube above the bottle cap with the enclosed 
plastic clip, can I then just pour out the PT Sel Black ink and just 
pour in the new MIS FS black ink and remove the clamp?  Are there any 
problems I need to watch out for when doing this manuver?
     I gather from the threads I've read that as of this time no one 
has found a compatability problem with using 5 bottles of PT ink and 
1 bottle of MIS ink.  Is this correct?
     Thanks in advance.

Matthew Kraus