I haven't even tried a feeler gauge on mine, when I install the stator over the rotor I just cut a piece of thick manilla folder, about the same thickness as a plastic milk jug, which is what some people use, and wrap it around the rotor until the three bolts holding the stator in place are tight. Then pull it out and have an even gap all the way around...
You may still be able to hot wire it, if it's just the charging side of the alternator that's shot, you could take the side that runs the headlight and use it to power your ignition, ride home without a headlight...