Hi, New to the Forum. I am a Electrician by trade but an all around do it yourselfer. I am in the middle of an addition on my house and before I close up some walls I want to install some ductwork for a future install of CAC. I purchased some oval duct to pipe from my attic through the non load bearing walls of my walk in closet and into the family room ceiling. The family room is rather large @ 17x24 so the plan is to install 2 8'' oval ducts into the room. One duct is straight from attic to the family room and the other will be a 90 to push it further into the room. My questions are should I transition from oval to round after the 90? In addition I would like to know the proper names for the pieces of ductwork that the diffuser will eventually attach to. Any and all info will be helpful as far as nomenclature of ductwork parts that I might need to know. Thanks
Tom