Thank you Allen! These are good items to chew on. I especially had not thought about the house stack effect.
o The RMH would be in the family room in the basement, and the whole family helps currently tend our wood stove there. I am sure the heated bench would be a favorite place to hang out.
o The flue is constructed smack in the middle of the house, and not exposed on the side, so it generally stays warmer, and does not get cold. I opened the stack clean-out door, and lit a match. There is currently a draw up. I think I should also test this on as cold a night as possible. The stack clean-out door also provided a convenient place to light some paper, to get a draw going, if needed.
o I realized the pipe-to flue connection is actually a clay pipe that the 6 in pipe fits into, that I could remove, and looking at it, it might leave about an 8 inch hole. I may be able to remove the clay pipe, and replace with 8 inch stove pipe (and seal), without further damage to the stack.
o I may need to seal air leaks to the attic, to reduce potential for back draft.
So far, I am leaning toward the 8" RMH solution. I don't have a measurement for the pipe length of the bench yet. Will get that shortly.
Does anyone else have any other caveats, best practices or bad experiences, related to items above?
Thank you! - Douglas