Unfortunately, this is sort of where things pause for a bit. I've got boards into OSHPark right now for Crazy Clock calibrators that use fixed OCXOs with the same footprint as what I intend to use here, and I want to build those before I design too far ahead of myself.

What I may do, however, is try and build a breakout board for the DAC. That by itself is one of the bigger unknowns, and it has a sort of whacky SOT23-8 footprint. I also want to experiment with the clock fanout buffer, but that's an ordinary SOIC-8, so breakout boards for that are easy to come by. One thing I want to do is try and breadboard the equivalent of using the fanout buffer as a driver and receiver with a "long" 50 ohm cable between the two to simulate actual service. The sending termination will be a 10 ohm series resistor (to eat reflections), and on the receiving end a 50 ohm resistor and 0.1µF cap in series to ground (AC termination). If that works, I can design yet another Crazy Clock calibrator that simply takes in an external reference clock and therefore eat my own dog food.