I have a home from the 1830's. One of the ceiling boxes is extremely shallow and it can't accommodate a newer fixture because the there isn't enough space for all the wires. So I want to replace the box with a larger one. The ceiling is plaster and the chandelier I want to hang is about 5-6 pounds. The current box is just screwed to the Lathe. What's the best way to install a new box. Should I cut a larger hole in the ceiling and install wood bracing between the 2nd story joists then install the ceiling box and patch? Or should I cut a hole in the lathe and install one of those plastic boxes with the wings. Any help would be much appreciated.