- Small notes are likely to be grace notes if the bar voices resolve without them.
- I think it's fair to assume that all staves within a line will have the same key signature changes. If signatures across staves match there's a decent chance they're correct.
- Regular accidentals can be very close to key sig accidentals. I guess there's only 14 well defined key sigs to worry about (multiplied by two clefs that I care about), and they grow in a simple pattern anyway. I'll just check that the accidentals at the start of a bar match this pattern.
- Finding the pitch value of a flat is a little harder than I thought. Next time.