Ok, so maybe I'll just get the FRK-less 703, and ditch the 2" foam. It just seems a shame to pay extra for FRK, and then still need something for the mids/highs. Kill two birds with one stone kinda with getting the regular 703.
Also, I was looking at the absorbtion coefficients, seen here:
http://www.bobgolds.com/AbsorptionCoefficients.htm
and it looks like 6" 703 would do an even better job at 125hz, which is right around my problem area. Does anybody know how this would do at around 50-125hz, or is this membrane-trap territory? Or do you guys think 6" 703 might be overkill?