Yeah the C13's are cabinets. If you can build your own do it. Thats even better beacuse you can get all the measurments and cuts out of the way when you build it.

The main idea w/ ventalation is you want fresh air(intake) to come in the bottom of the grow area-through the plants and finally out of the cab.

The way you get the spent air out is w/ high powered exaust fans:can fans or squirl caged fans. I use can (inline) fans. But you also have to take care of the odor so you hook up a carbon scrubber to the exaust fan. The fan is so powerful that when you hook it up it will suck air through the intake holes at the bottom of the cab(passive intake).
Look at as many cab grows as possible to get the idea of the ventalation and fans

Having a fan blowing on the canopy is good for the plants. Its spreads out the CO2 in the fresh air to the plants.


As far as dimensions, If your using a 1000 watt make it Large somthing like 5'x6'x7' +/-