An 8" inline is plenty of fan for this application. Watch out for variable air resistance after the tee- You may have to install some dampers to get good flow through the farthest intake.

You'll want an atmospheric/environmental controller to regulate your temp/humidity. You won't be able to regulate the two spaces seperately on a single fan, short of some highend HVAC work. Worry about flower if you're only regulating one.


Don't stress over intake temps- colder air will just cool the room faster. Make sure you have good air movement w/in the rooms to prevent stratification. Pipe heater elements won't do crap for air- contact time is too short.