How to make a blow through box

I went ahead and bought the open box one from Sonix. I'm pretty sure that I'm gonna do a blow-through in my truck, seems like the best way. yes sir i have a 93 s10 with the hole cut out for a blow through. i figured that was enough air space just not sure exactly how to build the box. i. never done a blow through. my concerns are how big to cut the hole out through the cab, should I make it as big as the box? or can I get away.

Dual 15" Subwoofer Box 4th Order Blowthrough. How to build a subwoofer box by granrhin.com Best Subwoofer, Subwoofer Box Design. Also do you guys think this will be a good set up? any ideas are welcome but I do .. How does it compare to a regular blow-through design. This is going to be the first time I am building a blow through for a When building the box do you build a back piece for the box with a port to.