I should add a note here about the system oscillators. The ICU timing methods have trouble with temp compensation on the main system clock. So the diode methods fails on a RocketScream Mini Ultra because it's temp compensation kicks in at 20C - dramatically changing the main clock frequency, and creating a fierce discontinuity in the data. Not sure if that applies to the moteinos, but it's something to watch out for with any time based method. While the clone board clocks are affected by temp, the effect is smoothly absorbed by the S&H constants.