On Sat, 10 Nov 2012 18:18:44 -0000, Lawrence wrote:

Can you not fit the largest flue and them put a spigot plate at the
bottom to match your stove?

You can as in physically but I don't think the BCO would like it as it is
probably against the installation instructions of the stove.

A large flue will slow down the flow of gases, the longer they take the
cooler they get and more chance of tar/soot deposition in the flue.

It will also affect the draw. I can't decide if it won't draw enough,
large column of air that will be hard to get moving, or draw too much,
wind over chimeny pot sucking a 7" column of air due to the venturi
effect being rather more than a 5" flued stove would want. Or a
combination of both depending on conditions...

--
Cheers
Dave.