box dimensions

here's da deal i have 2 5oo/1's for 2 12w6's in a ported box i had built for 2 w3's. i have pop trunk already installed. i need to know what kind of box i need 2 construct to get the most spl's without sacrificing sql. where would i get the dimensions for a box that would house 2 w6's.da back and front and possibly da inside will be plexi. i'm also not sure if i should fire them towards each other or thru the rear deck. also i have the alpine 7998 deck with da digital eq and i'm having a hard time tweaking it does any1 know how 2 use it. any plans or layouts would be cool 2 help get me started.
:apoke: