Just wanted to chime in and say that in all my years in this hobby I literally heard of braining working ONE time and it was just recently.
I always suggest being consistent when offering. Feeding the same prey the snake was eating before coming to you in the same method is typically what gets them started.
Gorgeous WLP by the way. I've been casually looking for a CBB for a bit. I'm running out of room, but a WLP is definitely on the short list