question

You don't have to change the capacity for this. In fact if I assume correctly that the operator is supposed to first do the setup before moving on to the next item and processor, that wouldn't get you all the way there.

You can control (to some degree) how the operator can use the available capacity with the Break To option. If you set it to Same Load Station, the operator will not travel to another queue to pick up more items, even if he has free capacity.

Furthermore, to control in which order pending tasks are done, give the tasks different priorities and preempt values. The setup tasks for example have to be able to preempt other tasks, because the operator will have already started the next transport task sequence when the setup tasks is queued up.

change-op-capacity-fm.fsm

For completeness: A good place to change the capacity would be the On Load trigger. There you can change the capacity depending on the station that the item was loaded from.

if(station == Model.find("Queue1"))
{
    current.setProperty("Capacity", 20);
}
else
{
    current.setProperty("Capacity", 1);
}