Depends on how big bulbs you go with.

You generally only need or want exhaust...not intakes.

Go with passive intakes...2 small one way flaps for each 4" fan. Do not use computer or cpu fans. Get a real exhaust fan from THD and place it highest in the box and place your intakes lowest in the box.

You want to develop negative pressure so you are sucking in cool bottom air and expelling higher hot air. Everything else must be tight for this to work.

Be sure and get some of that pre-filter black fiber stuff from THD as well (Near the air purifiers.) you DO want to filter the incoming air PRIOR to getting it in your grow box. Wrap the filter and clamp it on or tape it on the intakes. It also will help darken the light escaping.

Good Luck