> An OCXO will (usually) have less short-term jitter and better stability with ambient temperature changes than a chip-scale atomic clock module, but will drift more than the atomic clock long-term.

Indeed! And that short term stability of a (good) OCXO is most impressive, you can fairly easily outperform a GPSDO and with a little work and a lot of attention to supply voltage and other external influences you can even (short term) outperform an atomic clock. But aging is a thing, you'll need to re-calibrate almost every week if you care about that kind of precision. I have a bunch of different standards to compare with each other and the first time I got lucky with a very good OCXO I was wondering if I had made some kind of mistake, it was that stable.

That gravitational bias thing sounds very interesting, I knew it existed but did not realize you could trivially demonstrate it like that, I'll have to try this.