Can I ask abit of a technical question?.....
I'm a process Engineer - pipes/pumps/ducts/etc....what sort of max flow rate are you taking in through the intakes and hence we can do some calcs?
I think it's usually measured in grams per sec g/sec.
cfm is another - but is changed with pressure - ie: is 5% lower at the front intake than at the throttle
body - whereas g/sec is constant.
I guess for the purpose of an intake calc - we can neglect the 5%

say 500cfm*= 14.1m3/min = 16,920 g/min = 4.7g/sec

Whatever it is, you can then calulate the pressure loss through the system. Pressure loss there is lost suck = lost performance - that determines if you need 1x 50mm or 75mm or 2 x 75mm intakes and determines the cross sectional area of your filter as well. I'm guessing if you can keep that loss to <5kPa - you're on the money.

choose your poison

* at "normal" temp (0degC) and pressure (101.3kPa) air weighs about 1.2kg/m3