viscountian, I'm sorry I am not familiar with bars that fit onto rotary lawn mowers to remove moss. Perhaps someone else can help with that. But, I can tell you a broom will probably do a better job. That's all you need and it's much cheaper. LOL Maybe it will be more labor though.
To prevent moss, follow the instructions of lawn maintenance in my second post on [url=https://www.helpfulgardener.com/forum/viewtopic.php?t=13213]this thread[/url].