The PCGS statistics odometer now moves 7 days/week as the US crew is working Mon-Sat and China works Mon-Fri. The Chinese Monday is US Sunday so those stats show up Monday morning US time. Almost 1K coins were added from China overnight. To put that in perspective, total coins last qtr was 447K, 8% outside of the US (35K outside the US).
Now that I have long term instead of short term gains, China is the number one reason I'm holding.
However, I'm guessing that this Monday business is going to take a few quarters of observing before you can use it to make accurate predictions. I remember that the PCGS estimates were off at first when you were using them and then you figured out a way to back your way into better predictions.
For now, the best we can probably do is observe growth in that Monday number. Maybe on the next US national holiday when we get two days of international data free from US noise then you can evaluate to see if Monday's are high/low/average vs. other days of the week.
Regardless, I appreciate what you're doing just thought I'd offer some insight on how to potentially refine the process.