Thanks, everyone.
In a post about my new build, I was asked about this bass. Rather than place the answer on that thread, I'll put it here.
How is the SK1 holding up?
A little under two years and a couple of hundred gigs later, it's doing fine. Here are some observations and experiences.
I'm still happy with the overall tone. It gets the P-ish and J-ish sounds that were intended. You might say it sounds "woody" which is what I wanted, and which I think is hard to get in a more-than-4-string bass. I recently got out my import Lakland for a gig in a smoky room, but I didn't like it at all, it sounded too electronic for me. Which might be good for some people, but is not what I want.
I still find the treble cut of the preamp lacking, which is why on the new one I'm using a pre that also has a passive-rolloff-style treble cut. On this one when I want a very deep tone, I need to roll up the bass somewhat as well as full-cut the treble.
It has a few dings, and one good scratch. That doesn't bother me. There's a small spot of finish wear-through by the neck pup, which has turned gray, as maple does.
I took a pic of it recently and in the reflections noticed the somewhat uneven surface on the back of the headstock. Next one should be better.
It still has the same set of D'Addario EXL170-5SL nickel wounds on it. They are a little duller, so I have actually dialed up the treble on occasion, which isn't my normal practice. I'm waiting until the Dark Storm is ready to string up before I change the strings on this, so that I can test these strings on the new one, to confirm that the SL lengths will work before I buy a fresh set of strings for that one. The G string is pretty notched by the frets, though.
The B string is a little dull. When I change strings we'll see how that changes.
The frets show weird wear in the places I bend them, but it's not actually strange wear. What it is is a consequence of the fanned frets. On a standard parallel fret bass, you get parallel lines along the frets from the string windings, but they're not too noticeable. With the angled frets, these lines cross the fret, and it looks odd. But I don't think the wear is any deeper.
The balance is good.
I never bought the strap-mounted locking parts for the straplocks, I've been using the lugs as regular lugs.
Playing up by the bridge, with thumb on the bridge pickup to get Jaco-y, is a bit more difficult on the fanned frets. Due to the geometry, you can run out of G string, until you learn to adjust hand position.
After a year and a half, I replaced the battery.
I recently did some adjustment of the action, to see how low I could get it. To do that I had to take out the saddle screws, and grind a mm off the tips so that I could get them all the way down to the wood saddles. They are ending up being raised up a bit from there, but not as high as they were. For the second bass, I'll use shorter screws. The grinding afterwards is a pain.
When I had the saddles out, and the strings running directly from the string anchors, the G and A strings were just at the exact way-too-low action to get the most awesome sitar sound from the buzzing against the frets. Too bad it don't play in tune due to the change in scale length, otherwise I'd use it as an effect.