I guess I'll jump in on a year and a half thread.
Soon after getting my used OM-21 over a year ago, I put on a set of Elixir Nano PB lights. They were fine, but I later replaced them with DR Sunbeams. I put on my third set of Sunbeams last night. They have a great sound, last a long time, and feel great. Just make sure you follow the directions in the box before cutting them.
Bill