Bruce; You may be able to get your answer by inference.
Spec out an existing total THX system package.
RE rear centre: I was told to try & match my front centre as close as possible so I chose per size & type of speaker & materials & the specs. I have never seen a speaker sold identified as a "REAR" centre.
RE Select: It seems to be on some pretty inexpensive (low cost) models.
Question: Dolby 6.1 vs DTS 6.1 are the rears supposed to be dipols for both? I was told to use Bipolar because of the DTS ??
Dougofthenorth (starting to question everything "I was told")