I've used a wheel collar and drilled a hole in it for the wire, solder it in and drill out the hole to clean solder from the inside, slide it over the glow plug tighten the set screw. You might put a small non-ferrous washer under it to keep it from shorting out. An easy connector for servo arms also works well too.Solder the wire to the progecting stud ,slip it over the plug and tighten the set screw.