I have a new Osburn 2400 Insert setting down stairs, and I am putting my install plan and parts list together. I measured my chimney today and from the top of the insert to the top of the clay its 23 ft 6 in, and its all a straight rise (no bend or angles). I thought I had read somewhere about that causing an excessive drafting problem? I want to make sure I get the most effeciency and best burn times from this insert. Can anyone see an issue with a setup like this, and what else should I watch out for in this install?