My old lady saw a picture of a bulkhead in a living room (not in a basement). She wanted to put pot lights in them due to the current crappy lighting situation. I have no clue what kind of building supplies & material i will need to do this, besides the drywall. The length of the wall she wants it on its about 20 feet long, and it is an exterior wall which I'm pretty sure is plaster. Any help would be greatly appreciated!! Thank you in advance.