Over the several months that I've been collecting information on installation of a range hood vent, I've learned quite a bit here. So I thought I would pass on this "best practices" info that has been very helpful to me about the ductwork. It's for a Ventahood ( I think) but seems pretty generic to me.
It doesn't answer questions about induction vs gas but it did help me determine exactly what size ductwork to use, etc.
It also mentions at the end :
"Since smoke also expands as it rises, the hoods sides and
front edge should extend 3" to 6" beyond the front and sides of
the cooking surface"

I knew the recommendation was to increase size on the sides but I didn't know about doing that in front. Well, don't think this is required by code so we will pass on this requirement but if we had problems, we might consider moving the vent away from the wall (and extending the ductwork.)

So much to think about. I don't have a G.C. to pass this task onto so appreciate all the tips here. Hope this stuff I'm posting here may help someone else.
Best Practices - vent hood