I found myself back in the city where I bought the Gretsch (nearly two hour drive each way from my fairly isolated small town) today and I returned it. Was one of th best looking guitars I'd had in my possession, but it just had way too many hurdles to become something I'd actually like to play.
Visited a mom-and-pop shop afterwards and bought perhaps the ugliest guitar I've ever had in my possession (and that includes my DIY weight relieved 335 atrocity). A used Harmony Juno in "Rose" which is basically pink champaign metallic. It's a terrible body shape and a terrible color (this coming from a man that wears a lot of pink, as noted in the Soundcloud profile pic). But it actually sounds like what I hoped P90s would sound (and plays/feels great). Upper midrange snarl. High-ish output. Doesn't sound Fendery at ALL -- none of the stringey-ness that a tele or Strat has -- but does still have a more open top end that makes it sound like a single coil, not a humbucker. Even with the upper midrange and snarly output, still also have some spank to them.