Okay, so I've been playing this one quite a bit in rehearsals over the past couple of months, and I decided to make three relatively major modifications.
1. Neck profile - It became pretty obvious pretty quickly that I left this neck quite a bit chunkier than I should have. I was a little paranoid, not wanting to accidentally break into the truss rod route, but wow, this thing was a baseball bat. So, after some careful measuring, I took my Shinto to it, and took a little more than 1/8" thickness off the neck. The profile is flattish, which may need further refinement, but this should help playability a lot.
2. Headstock veneer - Purely an aesthetic choice, but I decided that the peghead needed a mahogany veneer stained to match the body. It's a little fussier to add the veneer after the headstock is finished, but it turned out pretty well. I put two coats of stain on the veneer before gluing it on, and I masked off the edges of the headstock to handle any excess glue. I used a scrap piece of ply as a caul, and a little bit of the glue seeped through the veneer and stuck to the caul, but a sharp rap separated the two, with only minimal sanding/restaining necessary. Before removing the caul, I scribed around the headstock with a sharp knife, which worked really well to trim the veneer to shape. Then I hand-twisted the right-sized drill bits through the tuner holes (brad-point bits, which scribe cleanly around the perimeter of the hole), which worked reasonably well. The same sharp knife cleared away the truss rod route, then I hit it with two coats of the same tung oil (Formby's) that I used for the body.
3. Electronics - The Villex PRTB is a seriously cool little gadget. But it wasn't cutting it for me on this instrument. It thickened up the bottom like it should, but the result was still too midrange-focused for my liking, with not enough adjustability. So I installed an Aguilar OBP-1. Never used one before, but it's two-band, boost-only, which seemed to me was exactly what was needed. First I pulled the existing wiring completely. Then I routed for the double battery box, and installed it. I used a 500k push-pull pot for the volume knob/passive bypass (still paranoid about relying on batteries during a gig), and purchased a 25k/25k concentric pot from bestbassgear.com - it's actually an EMG volume pot, and so it has audio tapers, but this wound up working to my advantage, as I believe this provides a more gradual boost for the first half-turn of the knob. Didn't want to drill another hole, and I really didn't have room for one anyway, so the concentric was necessary, but I also had to change the knobs, so my bestbassgear order also included two chrome knurled ones. They don't look quite as good as the original vintage-styled ones I used, but they do look pretty good, with the other chrome hardware on the bass. Finally, after lots of soldering (not my favorite activity), and a bit of troubleshooting with the multimeter, I stuffed it all in and buttoned her back up. Preliminary impressions are positive, but I won't really know how well I like it until the next few rehearsals. I am definitely excited, though!
I'll report back in a few weeks with a more informed impression!