What is the scale ratio for an annotation family?

I'm trying to create a light fixture with some symbolic information to display when we plot our plans so as to match our standard lighting symbols. The problem is I can't quite figure out the scale difference between creating the object as an annotation family and bring it in to the light fixture family so that it is the appropriate size.

The only other option I have is to create a symbolic fill in the light fixture family, but that does not seem possible.

Anyone have any ideas where to go on this?