Most schools will have an idea how many classes they want each staff member to teach. It would be great if this could be stored in Teaching Manager or Timetable manager. It could be really helpful in Cover Manager, working out who should be first picked for cover. I make various reports that tot up how many pupils and how many classes each teacher sets but have to add a column in by copying and pasting in from another spreadsheet.
I don't want to use a custom field in HR manager as this is not really an HR matter but a Teaching/TT matter and it also won't have any of the useful integrations that an iSAMS provided field would have.