I'll soon be installing my new Jotul F600 CB woodstove. I'm using a 6" ss flex liner in my 13"x18" tile flue on a 17' run down the chimney. The stove company where I bought my stove and chimney liner kit sells its flex pipe off a large spool. Both ends of the pipe were pretty ragged, so I cleaned them up fairly well using a utility knife and hacksaw. While working on the ends of the pipe I could tell this flex liner is pretty stiff. It is currently in a circle with a 5' diameter. I know I'll need to send it down my flue as straight as possible and I'm wondering if anyone can chime in with some advice on the best way to accomplish this. It seems it would be unwieldy to straighten it out on the ground and then try to carry a 20' long piece up on the roof. I sure can't see myself somehow getting that long a piece vertical in order to slide down the flue! I've watched some YouTube videos and they seem to be unspooling the flex pipe as they feed it down the chimney, but this stuff I have is way to stiff to do that as smoothly as the video shows.