All very good shots, i dont have an 18-55 so i cant comment on that, i was using a macro lens. you could try it at f13 again as that seemed to produce the sharpest shot and just reduce the shutter speed to 1/6000 or 1/5000. For focusing i switched to manual and used live view + the info button to zoom so i could nail the focus, then out of live view to take the shots. I get through boxes of matches as well
try using more than 1 match, tape a couple together for bigger flare mess around with it. I havent a clue what c108 is
Derek