Need advice on CFMs and dual ballast

Hello fellow RIUers,

I am in the process of changing my grow room around, upgrading basically and I could use a little advice. I apologize in advance if these topics have been covered extensively anywhere in RIU.

First off I havee been looking to upgrade my ballasts and I came across the dual 1000w lumatek ballasts. I need to upgrade 4 1000w, this would be perfect to save me a bunch of money by going dual. Are these things reliable as the seperate ballasts? Anyone here can give me some pros and cons if you have used them?

Second of all I have been searching throughout the site on how many cfms I need to cool 4 1000wers. Have magnum hoods 8 inch ducting. The ducting has to run about 10 feet across with one bend coming in from the ceiling. I am looking at running a y duct with the fan outside of the room. I am located in Montana so my concern is mainly summer time when temps can reach up to 100 degrees. This is a sealed room with a split ac. Anyone know a way to measure CFMs for this kind of setup?

Kinda long I know but thanks in advance!

dual ballast should be fine and save some money. as for cfm with 4 1000watts most people try to get 100-200 for 2 so 350-400 would suffice i guess.

Hmmm ok guess I have a place to start with/ I know it is such a specific question. I am nit picky on details. Thanks qazwers for taking the time to reply.