Repeat readings were usually within a few points of each other. The second and third blood pressure readings tended to be closer, so in future I might just skip doing the first reading
I only took readings throughout the day once, it's tedious! The highest (but not by much) readings were around 5pm and 8pm, as expected. Like with other measurements, mornings seem better for long-term tracking since the confounding variables pile up during the day.
The only complication is that my blood pressure pressure appears to decrease slightly throughout the morning (~1.4/2.3 mmHg per hour), but this shouldn't be an issue as long as I avoid very early or late measurements.