How can i transfer Vertex Paint data to blueprint instances?

hello, i’m working on vertex painting for a group project and i noticed that you cannot paint blueprint directly and only the placed instance.
We have around 75x16 building to paint, so painting them one by one isnt really doable…
instead what id like to do is, to workaround a solution to only paint the 16 building BPs and update the vertex paint data of the other one.

What i tried :

I already tried to duplicate, paint, then Harvest to a new BP class but it duplicates the parent on top so it’s not working either. if it worked i would have deleted the non painted version and replaced the instances with the painted one.

Anyone with an idea ?