Just a question why a push push design? I do understand that you want to reduce cabinet vibrations but why not simply brace you box? I might be wrong but the displacement of those drivers being run from 200 watts is hardly wall shattering power! I am not familiar with that Amp however from experience even with pro audio amps running an amp at two ohm is risky business, also that amp is going to clip trying to run those drivers which are rated at 150 RMS each, i really do think you need to think about budgeting for a bigger anp that you can run at 8ohm rather than 2! Even a large vented box for those drivers will still be reasonably small so if i were you id design a large vented box with two forward facing woofers. Either way good luck with your constuction
Regardless please post contruction photos, they give me that warm fuzzy feeling
Oh and what are those drivers sitting on
looks like a box...