Need some help figuring out specs for a box for 4 12's. (EDITED)

[JBERK]

Basically here's the gist, I'm putting 4 12's in my Ranger... or at least I'm going to try to.

The dimensions of the space I can use:

Width : 52" (with interior panels installed, can probably get more if I remove them)

Depth : 12.5"

Height: 20.5"

I can't go outside these as I'm trying to keep the box under the window line and the depth is important because I have to sit with the seat all the way back. Here are the key specs of the subs I'm trying to use:

Outer frame diameter: 12.5"

Hole cutout: 11 1/8 "

Mounting depth: 7"

I would prefer to keep them all level with each other like OOOO and not up and down like ºoºo if that make sense? I know its a tight fit but I'm wondering if someone can help me otu coming up with the dimensions for the box? I'm aiming for 1.5 cu feet per sub and I'd like to port the enclosure around 32-33hz if possible... I can pay for a design, but I don't have much extra money.