Making some progress. Got the neck pocket routed out. Not as accurate as I want, and a little sloppy on the sides, but it work okay. Here's a mock-up.
Also got the pickup cavities routed out. Turns out on a jazz bass, the neck and bridge pickups do not have the same dimensions. The bridge pickup is a little longer. Does anyone know why? Class? Class? That's right, because the strings are not actually parallel. They spread out as they go from nut to bridge... just a little. Took me a few minutes to catch that little detail. Yes, that's my sweat I'm putting into this thing.
Here is the active preamp I had in the burl walnut Bass. I won't use the mounting plate. As I mentioned earlier, I will mount the pots directly to the maple cap.
Here's a pic of the control cavity. It is not beautiful; don't judge me. Notice the holes drilled for the control knobs.
Next step is the control cavity cover plate. I will make that out of zebrawood. I have to make a template first. Oh joy. To do so, I want to copy the outline of the control cavity. I taped some paper over the cavity and used a pencil to mark the edges.
After that, I drew a template where part of it followed the curve of the bass. Traced the outline on to the zebrawood and cut it with the bandsaw.
Here's a mock-up
Next up I have to make a template for the cover cavity. I want it to mount flush with the back of the bass, so I will route out only 1/4". I will make the template out 1/2" MDF.
That'll happen in the next few days.