Amp meter or Volt Gauge ?

Your alternator shouldnt burn up your harness unless the wiring is designed for a 37 amp, and you have one substantially higher, or you had a short somewhere and there was no fusing/breaker protection for the wiring. Converting over is easy and not a problem, and would help cure problems of inadequate wire size for a high output alternator. It wont help you though if your large current draw (huge stereo w/amp etc.) is connected at the dash. Voltmeters generally work good, but cant tell you if there is something drawing after you shut down. I always look at the ammeter right after shutdown, and comfirms me everything is off.