IF! IF! IF!
If in one hand and sh*t in the the other, see which one fills up first!
First thought?...Shoulda left that nc30 in here!
Chances are alot better of that maybe-someday-buck working OK on a 6" than the soon to be nc 30 working worth a crap on a 8"! Get a 6" and don't look back!
And Hogz is right, the 6" will have the stronger draft of the two...Smaller diameter = higher draft velocities = warmer chimney = stronger draft!
A 8" pipe will work better on reloads.
The cross section is way bigger.
I guess Bk and Buck have no clue about stoves.