[twvette]

I don't think a "raceway" design is a good idea either. If one AC is off that adds a lot of volume to try and pressurize and don't think you see this in residential/commerical either but not sure.

Yeah, I triple checked them. There is about 3 feet gap between them when look at the tape measurements compared to wall length. Further verification was can see the light reflect back with photo from camera where it does not do this on the ones that are connected.

Just my luck I took my bore scope home last trip as it would have been really nice to fully inspect all ducts to see if any others might be torn somewhere. They are cheap on Amazon.