That's still chokingly small. I would say ~60 sq in of port as a minimum (I'm using 73 for my current box)
What's your port shape?
I didn't mean it like total area of port, 16sq in per cube. Sorry i didn't explain it better! haha.
I built a box for a XL 18, Has 6.06 after, and 18 sq in per cube with 114 sq in of port area. Just to give you a rough idea though.
Oh, my bad. I thought you meant total LOL.
In that case stick to 12-16 sq in per cubic foot. I like to err towards the larger side of a port when possible
yeah im actually making a new box right now, and snowdrifter that alright haha, i was assuming u ment total