@Krileon
It could be an issue with the Blueprint delegate, as I know they Auto-cast their references. The delegate does seem like the best way to go about your issue, though, so it may be worth checking out the C++ implementations. If you want a link, I’ll throw you one:
There’s a lot going on, and a lot of control you have - with both events and multi-cast delegates.
I hope this can help!
-Zen 