Keep this in mind, when our ancestors started smoking meat, they didn't have all of the information we do now; it worked for them...
The main thing to keep in mind is that heat wants to rise due to physics and will find a way to do so. Now, in its journey to rise, it may get blocked a bit and create a hot spot, but the heat will continue until the hotspot is undercut and the heat finds a way out if the route is open.
Now, the next argument is; well I'm cold smoking so there's no heat.... Well, if it's smoke, it is heat and will find a way to rise...
I'd say build it as you can, try and keep it as unobstructed as possible, and see how it goes...
Charlie