Looking for advice and suggestions.  Buying a Sony STR DN-1040 (7ch) and Polk Audio TSi 500 floor standing speakers with a CS20 or CSiA4 center.  The rears (5.1 system) will be Polk in-wall units about 11' up from floor due to room geometry.  I need zone 2 for outdoor patio tv and sound, altho the sony needs an external amp for zone 2. Want to watch two different tv programs at both locations simultaneously.  Do I need to run a 75ohm coax from the outdoor cable box to the sony and then 4 speaker wire pairs to the outdoor speakers from the sony?  Can I borrow the two unused surround channels for outside?  Not sure how this works.