Do you mean air space, or actual plans on how to build the box?.
I would recommend a 1 to a 1.3 cft enclosure for those subs, and i also reccomend that you give them their own airspace(no shared enclosures) I had a pair of 8712's that sounded like **** in a shared 2.6cft enclosure, but kicked ass in a dual 1.25 cft enclosure.
As for plans, go bug those lazy bastards in the install bays, thats what i always do.