Why do you want to use one for Midi only? What kind of connections do you have...ethernet, parallel...these would connect the PCs if you want to bother. Midi doesn't use much disk space. What kind of midiman do you have? If it is a 4X4 or greater you just make the midi connections and in Cakewalk you set up the MIDI IN/OUT ports. If it is a 1x1 or 2x2 or 1x2 you will have to daisy chain the midi. You won't be able to access more than 16 channels on a 1x1, 1x2 and 32 channels with a 2x2 interface. This limits you if all of your modules/keys/controllers have midi channels.