I built a 12" WO32 with Mach5 maw 12"s
they are not all that sensitive but I like them. My Sub was not what I call weak but not       " loud" I was using 100 watts where I could have used at least 700 and in my application it was nice and would raise an eyebrow once in awhile.
You need low QTS, low Vas Low Fs in that order IMO I cannot remember the specs on the maws but they sounded good to me.
Mine was the same as the 10" except it was 2 inches bigger to accept the 12". I squeezed the first bend just a little, maybe a little less a quarter of an inch and went from there.

Or just build it the way Steve designed it and just accept the sweet comfortable sound the WO32 makes.
the WO32 does not have the output of the WO or other subs, it is more relaxed and softer in a way. I can use the same driver in the WO and the WO is loud where the WO32 is not. but its so much better sounding to me. Its a sub without a bad temper and does its job comfortably with class and accuracy.

You may be expecting something the WO 32 is not designed to deliver , its not known for its output. The WO hammers you directly and the WO 32 plays nice and once in awhile gives the wall beside you a good wallop and you get the concussion effect with depth the WO does not have.

Gex

where you how you place the wo32 is VERY IMPORTANT.

turn it around so the mouth or opening faces AWAY from you, maybe into a corner, try it in a few different spots.

my wo32 can shake things off the wall with less than 100 watts if located right, when located wrong it sounds like a bad midrange  [smiley=18.gif]

with a subwoofer

PLACEMENT IS EVERYTHING