I am going to drop a flexible flue liner into my chimney. My issue is that my clay tile liner is 8" x 11.5" OD. or 7" x 10 1/2" ID. Obviously I cannot get an 8" liner in unless I squash it into an oval. Combine this with the fact that it is approximately a 30' run, and the project is likely impossible. Can I reduce it to 7" or even 6" without problems? For the record, the chimney is dead center in middle of the house, it goes through two floors and the attic. I also have a 8' horizontal run to the chimney from the EKO.