You are too rich on bottom it sounds like. So that is prob the reason for popping plugs and unfavorable acceleration and inconsistent performance. You should return the low and high needles to flush and re tune from there. Make sure the engine is already warmed up for 5 minutes or so before re tuning. You need to tune the needles together especially the low and idol needles. They are both affected by each other. When you start changing one of those needles, you have to compensate with the other needle to balance out the change. Then you'll have to change the high needle too to stay in over all balance of the tune. Its trial and error. WISH THEY HAD FUEL INJECTION!!!!!