Agreed, you are much better moving cold air towards the stove, rather than warm air away from it. Another factor is that it's a code violation to have any kind of air INTAKE within 10 feet of the stove, but outlets are OK...
It is also MUCH better to use rigid duct work than it is to use flex... Flex causes huge amounts of turbulence and airflow resistance, especially if it is not fully extended, run straight, and cut to length when it's installed... It's a labor saving hack, that will give you a lot less airflow than rigid, unless you compensate by using a bigger, more expensive, higher operating cost blower... Whatever form of ducting you use, make sure you seal it well, and insulate it to the same value as the ceiling. If not, while you are going to lose less heat than you would if moving heated air (heat loss is a ΔT function) you are still moving heated house air through a radiating surface in a cold attic...
That said there are as many, if not more, failure stories of this sort of effort to move heat as there are success stories... There are so many variables, it is hard to predict whether or not it will work in advance, especially for those of us in places far away that have never seen your setup.
Gooserider