For every other node the size property determines the, well... the size of the node. Please don't add extra width and height parameters for that.
You are right about SPINNER_WIDTH and SPINNER_HEIGHT, if you get a closer look, you'll see they override node->size property in UI_SpinnerNodeLoaded. Please use node->size.
/off
awww, This node has way too much data hardcoded!!
/on
Edit: width and height are aliases to size[0] and size[1] AFAIR, maybe adding them to extradata failed due to that.
-geever