I’ve done quite a bit of reading on the site but can’t find my specific scenario.  I’m building a new home in Portland, OR that has a flat TPO roof over polyiso build up.  The eaves extend 6′ out over the walls and the soffit runs at an angle from the roof edge back toward the house dropping about 3′ at the house.

Walls have a James Hardie shiplap siding installed over vertical furring strips, 1″ rigid insulation and rain screen.  Siding vents are installed at the bottom of the wall so there is air flow behind the siding. The interior ceiling and walls will have sprayfoam against the roof decking and blocking above wall separating the eaves.  This leave the eaves as their own cavity with polyiso insulation on top. 

My question is should I install a continuous linear vent in the soffit? I have been told I don’t need it – which I would prefer for a clean look.  But I’ve also been told I do need it. Appreciate any insight or reference to articles that I may have missed.