Help getting a good sound out of Epifani PS-112

[Rockin Mike]

I have a Genz Benz Streamliner 600 right now driving an Epifani PS-112. It sounded OK (not fantastic) in the store, but at practice I noticed the lows were way too loud, and they were boomy and muddy, and there was a lack of midrange. I EQ'd the bass down quite a bit and stacked it with a Hartke HX-112 which helped compensate the mids, but the bottom end was still mushy and the whole rig lacked definition and articulation.

Is this a natural property of 1x12 cabinets?
Is this just the way of the PS-112?
Would it respond better running with two PS-112s?
Would it sound better with a different head?

I'm comparing it with my other rig which is:
Eden WT550 head
Eden D410xlt cab
SWR Redhead 210 combo on top
Is it just not fair to ask a lightweight rig to hold its own against that?

Thanks for advice and opinions.