If your school uses composite classes and you would like to not only limit the number of students in the class you can also let Class Creator know how many of each grade you would like in the class.
To enable this head to 'Future Classes', followed by 'Configure Classes' (this is where you would set the number of classes and enable ‘Composite Classes’.
Navigate to 'Class Settings', then add in the number of students you would like in each class. Please note that if not all students are allocated to a class they will appear ‘unallocated’ once you create the classes. You will be able to drag and drop them into the class that you wish or use one of Class Creators tools to find their perfect fit.
You do not need to do this for every class, just those that you know or would like to enforce a limit to.