A few years ago, we had our old house rewired. My electrician used Angelo's Fan Brace (now called Westinghouse Saf-T-Brace?) for all ceiling light fixtures. He used the 1 1/2 inch octagon fan box.

In several locations, the ceiling has an extra layer of plaster and/or wall board laminated over the original plaster. As a result, the ceiling box is not flush and mounted about 1/2 inch too deep. The box clears the wood lathe, but not the final plaster or wall board.

I am hanging several new light fixtures. We are not using ceiling fans. Should I replace the boxes with the 2 1/8 inch Saf-T box to make it flush with the ceiling? Does anybody make a 1/2 inch (or 5/8 inch) mud ring for this application? Alternatively, can I use the existing box and spacers to make the fixture mount flush to the ceiling?

Thank you!