How much lower can my intake cfm be?

Will a 6in 450cfm intake be enough?
I have a room with approximately 2200cf and about 300cf of the room will be split and used for veg. I will be pulling 8in 750cfm exhaust threw CanFilter then threw multiple hoods on two separate runs. There will be a second 8in 750cfm fan at end of run to assure the 750CFM is just that. The other smaller 300cf veg area will be passively intaked from the larger remaining area described above. Making both rooms sharing air and intake. That room will then have a 6in 450cfm fan also attached to a can filter and going threw a single run of hoods, also with second matched 6in 450cfm fan.....>>Giving a solid total of 1200cfm exhausting.
I plan on intaking from a controlled room, and I DO NOT WANT PASSIVE!
Was originally gonna buy a 12in 1050cfm for intake and throttle down (if required) with speed controller, But was convinced (not easily) that a 6in 450cfm could supply my required 1100-1000cfm (leaving 100-200 for pressure) by speeding the fan in excess of its original output pressure (450cfm).
I just wanna know if my exhaust pressure will be enough to propel and pull my 6in 450cfm fan to around a 1000cfm or so? I know ill have a drag, just wanna know how much?
Should i go bigger or is it not required?

I know Im going on for days,.. But thanks in advanve for reading, and any and all help received.

you want to fill the room in approx. 5 min. so do the math!!!!

i run a 90 cfm in my veg room that is 6x6x8 and a 280cfm for my flower room that is 10x6x8!!!

Yup. gonna be cleaning that air around 2min.

so if you got 500c.f. then you need to do at least 100 cfm a minute!!!

Dude,....you gotta be ripped. Please read.

if you dont want any passive air intake,you will need to maintain positive pressure in the room so your intake will have to be higher than outgoing air & you will need the room to be perfectly sealed 100%.this is done in some surgical rooms to control the air inside the room to make sure it is sterile.plan on doubling the cost or more to build such a room.why would you want this?
but if you sucking 1000cfm out of the room,then yeah,the negitive air pressure in the room will suck 1000 cfm from the intake,even if you have a 450 cfm fan or no fan at all.it will take the 450 cfm the fan is feeding it & the rest will be sucked in passively,mainly through the duct but also through any cracks air can seep into.if putting a fan on your intake floats your boat,go for it but consider it a waste of money unless your intake room is far from the grow room.

I guess my main thing is just putting too much strain on my exhaust fans because intake is so much less. Ya, I definitely don't want positive pressure in my room. And I don't plan on there being any cracks (want it clean and controlled) for air to be pulled from. Yes the intake coming from a controlled room will be some what of a long single duct run. And i understand that the 1200cfm (exhausted pressure) has to come from somewhere. BUT, WILL THAT BE TOO MUCH STRAIN ON THE FANS? LAST THING I WOULD WANT IS A FAN TAKING A DUMP ON ME BECAUSE IT HAD TO PULL CLOSE TO 1200CFM THREW A 6in HOLE WHEN I COULD MAKE IT LARGER?
Should i just take the fan back and make larger passive run from controlled room? Like 10 or 12in passive single duct intake from control room. Cause really, after thinking more, what good is the fan if it only pushes less than half the cfm i need? It would actually even cause more drag then positive pressure, right? Pointless?
Now im just thinking i Should'nt have listened to that hydro store dude tell me not buy a 12in 1100cfm fan and speed conttroller!
Inputs please?

understand that unless the room is hermetically sealed,you will have cracks.its not a big deal.the goal is to get 99% of the air from your controlled room. a too small fan blowing air in the direction the air is already moving will help the air along but will not be under a strain so wont burn up any faster.to large a fan will cause positive pressure in the room and force air and smell out the tiny cracks in the room. now you assume you are moving about 1200 cfm out but because of the restrictions from the filter & any bends in the duct,it is just an educated guess.to big a fan & you could create positive pressure in the room.running a bigger duct(putting the 6 in fan inside) or adding a second duct would not be a bad idea but I would be careful about getting to big a fan for intake.