I figure I’ve gotten a lot from here, so sharing something seems like the thing to do.
I created a graph to create a wall, place window types used in the project, set everything to a legend phase and demolish it appropriately. This all assumes that you are using the previous phase method for your legends. User will need to verify the wall type, wall location (currently set to 0,100 / (window width sum*2),100), and phases. I added a note indicating any custom nodes - if I missed one let me know and I’ll amend it.
Enjoy. 
Create-Families-Legends-Window Legend.dyn (38.1 KB)
edit: the IF node wasn’t working so it’s removed. also defined a function for Sill Height so it can be used in multiple places, in particular to define the height of the wall (Sill Height + Window Height + 3)
