Workflow action script - does anyone know what the maximum number of executions that can happen in one day before it would fall over? for example if we had 10,000 transactions per day and for each one, it would iterate through each line on the transaction (average - 10 lines), check and then store a number... what's the total usage in that scenario? And what's the alternative if this would fall over?

WF action script governance is per execution. See the documentation