The initial release, the code now seems stable and sync's well to other devices. The main.py code is designed to work with the WaveShare Pico-OLED-1.3 display, but can be adapted for others.
Calibration of the XTAL will still be an issue, as the stock Pico is built with a passive XTAL (rather than a TCXO - temperature compensated module). It is possible the replace the XTAL, this will be investigated to see the performance benefits.
For now my focus is shifting to building the PCB and validating that.