A couple of things here. First, it's wise to use an old plug for at least the first run because there can be tiny bits of swarf left in an engine from the machining. Aluminium is deadly to the platinum in the glow plug coil which could explain why your plug stopped working.

Second, from the sound of things you had the engine running close to being peaked out and this should never be done with a new ringed engine. Manufacturer's figures for the number of turns out on the needle are only a guide and they can vary considerably in practise. A ringed engine, especially on its first run, should be run as slobbering rich as you can get it. This means really really really rich . After that first run you can lean it out a little more but always have it making that 4 stroke sound, not the high pitched normal 2 stroke sound, for the next 30 minutes or more.