Ventilation in 4x4 Cab

Hey RIU. Long time no see. Not new to growing or RIU, but new to HPS and cab grows. For my next grow, I will be building a 48"x48"x7'6" total height cabinet. Leaving about 12" up top for hardware will leave my grow space height at about 6'6" and air volume at 104 cubic feet. I will run a 600 w MH/HPS in this 4'x4' space. To the growers experienced with hps in cabs I ask: how much ventilation? Right now I am thinking I will need two fans- the HPS in a cool tube with a simple duct fan, then a second fan with a charcoal filter for the grow environment that will pull air up from the bottom of the cab and let it out the back. Or, can I have the light with no cool tube, and simply vent the whole space with one large fan/charcoal filter?

With the double fan setup, what fan sizes should I use? Is a 6" 240cfm duct fan adequate for the cool tube?

To vent the grow space I was looking at the VenTech 6" inline fan and carbon air filter which is 440 cfm. With a cool tube in place, 440cfm seems like a lot of air flow in my 104cf cab. Would a 4" fan be adequate?

Any help is much appreciated.

What I would recommend is having (1) 6" inline (440cfm) fan. Carbon filter ducted to cool tube ducted to incline fan that pulls air out of cabinet. Carbon filter should be mounted high in area where hot air sits so your scrubbing air and pulling hot air out. Also get a speed controller ($25.00) for your inline...

Deff. Go with the 6" when I had my 4x4 can I used a 4" and regretted that purchase and beside the 6" inline is only like $30 more on amazon the have the venttech 4" fan and filter for $104 and the 6" fan and filter for $133

Idunno why I didn't initially think of going inline, filter -> cool tube ->fan -> out. Sometimes you need a second pair of eyes to point out the obvious. Thank you gentlemen. We can't like comments anymore? Well rep all around I guess.

rwbrock have you had any negative experience with speed controllers. I've read that they can damage the fan over time because they alter the sine wave of the AC and the fan requires a smooth up and down sweep. This is outside my area of expertise and possibly yours. Maybe it's bullshit and they last for years and years.

Mine is called the speedster and I got it from my local hydro shop. I haven't had an issue with mine or it affecting my inline fan. I will say when I had my 400 going in my closet it was almost always full throttle maybe 3/4 at lowest speed. I could see possibly if you always ran your fan at a low speed it may not be optimal for the fan?? I have had this fan with speed controller going for little over 3 years now.