So after lugging 500lbs of iron into my family room [with the help of 4 friends], I am self installing my Harman Accentra insert. The Harman manual is decent, but I find it jumps around quite a bit, skipping some important steps and even referring to non-existent diagrams. I have a 20' flue that I am inserting it in, all is well so far: I've got the 4" stainless steel vent pipe up the flue, the top plate and top cap are in place. My real question is about the installation of the vent pipe to the stove itself. The vent kit I purchased came with a male-female adapter, which I am using to make the connection. I am using the wider end of the adapter to attach to the vent pipe as it comes down the flue, then the smaller end goes inside of the stove outlet from the Harman, but it's fit on the stove outlet is anything but "snug" and airtight. Both ends are secured using the adapters built-in hose clamps. Is this correct? I was told by someone that it should always be like that, so creosote etc. will drip inside the stove instead of all over the outside of it. But I am concerned about the fit not being anything close to airtight. I read somewhere that I could use either a high-temperature silicone caulk or chimney cement to seal it better. Any suggestions would be greatly appreciated.