New Post: Trying to use SPCascadeDropdown and CAML to select from a massive list

I have a very large list of classes which I need to allow the user to select multiple ones of.

I have the cascade working fine based of the school the class runs under and all is good apart from its still hitting the throttle limit as the whole list is being brought back.

It seems that I should be able to use CAML and perhaps :
$().SPServices({

operation: "GetListItems",

To only pull back what the user selects from the parent but based on my lack of results I either misunderstood what it could do or I'm doing the wrong thing...

Can anyone point me to some examples please???

my working cascade is:
$(document).ready(function() {
$().SPServices.SPCascadeDropdowns({
relationshipWebURL: "/",
relationshipList: "Courses",
relationshipListParentColumn: "School",
relationshipListChildColumn: "Class",
parentColumn: "SchoolPick",
childColumn: "Class",
listName: $().SPServices.SPListNameFromUrl(),
simpleChild: false, // Added in v0.6.2
selectSingleOption: false, // Added in v0.6.2
matchOnId: false, // Added in v0.7.1
completefunc: null,
debug: true
});
});

I have a courses list, Schools list, and in this case a student list.