What would the symptoms of a slipped balancer be? Would the timimg appear to be retarded? Typically how much to they slip? Would it cause vibrations?

Thanks!

When a balancer "slips," the timing mark moves. For example, if it slipped 10 degrees and your timing is supposed to be set at 6 degrees before top dead center, you get your timing light and set it to those specifications. Though the timing light is telling you the timing is right on 6 degrees BTC, you're actually firing at 4 degrees after top dead center.
Set your timing by ear while using a vacuum gauge to get the highest vacuum reading at idle, take it for a test drive to check for pinging (predetonation) and continue to adjust the timing from there.

And replace that balancer ASAP.