Hey Mark thanks for the reply. Yes that should do the trick.
My original worry was caused because I thought I would have to check instanceof on several different Layer subclasses to know who to set a min/max on. That was going to lead to a question about interfaces (or rather the lack of), but since GraphicsLayer is the only one that supports setting min/max scale we can push that off for another day. GraphicsLayer will cover 95% of my use cases involving min/max scale for now so I should be good to go.
Thanks again