That example you show to SET after CREATE works when your doing the CREATE part, but if your trying to reference that Widget long after its created, from another widget or BP, then one. The CREATE function doesnt apply then, and the CAST function requires an object, which in the case of Widgets, there doesnt appear one to plug in.
I completely understand I need to tell it what Widget, but outside of the CREATE function, this doesnt appear to be possible.
The work around in my scenario, was to move all the VAR to Game Mode which works fine. Im not fond of it for memory resource management reasons, but it works.