How fast should my Cuckoo clock's pendulum swing?

Set the pendulum weight and note the time. Check it an hour or a day later. If it is running too fast, lengthen the swing of the pendulum by dropping the weight further down. If it is too slow, shorten the swing by moving the weight up. Keep doing that until it is running exactly right. Or, just get it close and reset it every once in a while. If it loses five minutes between windings, it isn't a big deal to just nudge the hands ahead while you are about it.