If Kef made a speaker with the same mid and tweeter as your 104s, I would buy 4 of those.
Dipole surrounds pre-date Dolby Digital 5.1 and 7.1 processing technology. Dipoles were really designed for the early dolby pro-logic processing with diffused mono surround. Think of your theater system as a 7 channel stereo. Would you use a dipole for the center, left or right? I think not. The dolby website recommends 5 "identical" speakers.
Dipole surrounds pre-date Dolby Digital 5.1 and 7.1 processing technology. Dipoles were really designed for the early dolby pro-logic processing with diffused mono surround. Think of your theater system as a 7 channel stereo. Would you use a dipole for the center, left or right? I think not. The dolby website recommends 5 "identical" speakers.