than hit you with the full concept diagram straight away, let's take it
in steps. The first two simplified diagrams show only those parts of
the diagram related to a particular scenario.
Round-trip analysis, same as it was done using Version-1 of the software: record a mono wave-file at the sample-rate of your session.
Using a portable recorder instead of a DAW when analysing hardware sequencers: the MIDI-signal track will reveal jitter in the MIDI clock; the Synth-audio track will reveal synchronisation drift in the second Sequencer/ arpeggiator/ drum-machine. (Use a synth whose own jitter has already been proven to be well under 1 msRMS.)
The full concept diagram. Compare this with the first two diagrams