L7 sealed enclosure

Here's a question for the pros:  I've got two 12" L7's and they're in a dual chamber MDF box (each side has 1.54 cuft) with each getting full RMS power from their own amp.  I know the 12" L7 handles 750 RMS in the compact enclosure (.88), but kicker says it'll handle the same power up to a Qtc enclosure.  The amps are kx800.2's so I can easily give the L7's 800 RMS each if I want to.  At the moment I've put poly-fill in the boxes and everything's installed, but I'm still waiting on a breaker to arrive so I can charge my caps and get these things running.

Here's my question:  In your experience, has the L7 been able to handle 750 RMS in a larger enclosure (closer to 2 cuft) or should I take out the poly-fill so the enclosure is just 1.54 cuft?

P.S.  I also have two glass enclosures in my car, one being an L5.  The enclosure was a total of 1 cuft and had very low output with poly-fill.  Once I took the poly-fill out, the output increased by quite a bit (more than expected) so I'm assuming that the poly-fill in the L7 enclosures will make a pretty big difference in the behaviour