I live in a doublewide trailor, The duct working in the trailor is no good and I want to replace it with flex. I have a brand new already hookedup 3 ton goodman unit that is supplying the original trailor duct work via 2 8" flex pipes coming from a 16". I need advise, I am not new to hard work but I dont know alot about duct work and so on and I would love help in the best way, along with parts list help. Here is a drawing of what I am going to do. I am going to cut new floor vents along the outside walls and make it easier to install and mantain the duct work. any help? Thanks ahead of time.