Yet another Kicker L7 sub/enclosure topic

[X3FBrian]

First off I have a 2014 explorer and my gear is as follows:

Kicker KXA2400.1

(2) L7S Kicker 15's

All supporting power mods including, big 3 upgrade, 200 amp alternator (factory) two D1200 XS batteries for the amplifier.

 

I'm looking for some recommendations on the best box for these subs.  I had a custom box built and it's dimensions are (3/4" MDF, double baffle on top)

 

39" wide x 19.5 " tall x 30" deep (exterior measurements).  The port is 16" tall x 6" wide and it goes into the box about 21.50 inches and stops there. 

 

Here is the box before it was finished for a reference:  https://imgur.com/MfsDbzt

Here is the box finished with subs mounted for reference:  https://imgur.com/X0t2TtZ

 

What cubic feet is this box per sub net?

 

Ok so lastly, the max dimensions I have to mess with are as follows:

 

39" wide x 22" tall x 36" deep  (a 36" box would be about 8" from my rear hatch)

 

What type of enclosure would be best for my application?  Subs up, port up?  Subs back, port back?  Does the port need to be flared like it is now?  Does the fact I'm over powering these subs by 250 watts per affect the box they should be put in?  I've heard some really really loud dual 15" square sub setups and for some reason, this just isn't doing the same and I am simply assuming it's because the box is just too small.

 

Thanks in advance for any help.