Typically it is not necessary to seal the stove pipe connections. Simple metal to metal with screws holding it all together works well. No draft will be lost.
The Direct Connect Base for that stove does not have a way to be screwed down to the stove. There is a handle that protrudes forward and can be held with one screw to keep it in place but that would not hold the collar to the stove pipe adequately to prevent and leaking.
Yes I am aware that draft should suffice. I'm talking safety.
I was planning on running the liner up about 6' to reach the first clasy flue liner which is 7" x 12" ID