I've never heard of the Big Picture method in particular.
Project-based learning can be terrific-- or a disaster if there are EF or anxiety issues in play. Often there's an assumption that if the child is gifted, the child has superior EF skills and can work independently toward a project deadline. This can result in long stretches of puttering and then terror, repeated over and over. Only if every project step is well supported would this be a good fit for a kid with EF issues and/or anxiety.
I think if she's happy where she is, and you think her needs are fairly well met there, I probably wouldn't move her.
