I would try, for that diam, double wicking. But have you tried the biggest CD wick, or any of the others? I hate double wicking and that is one of the reasons I switched jars. The thing to look for on the last half of the candle is to make sure the melt pool doesnt get to deep, the jar doesnt get to hot, no black soot on the jars, flame stay a nice height (not to small, not to big), doesnt flicker too much, i think this is about it. when it is all done, what I shoot for, you want a jar that is pretty clean on the sides, no nastiness on the rim of the jar, I like for the little bit of wax that is left to still be the same color (no black stuff in it), the jar to be able to be picked up without burning myself. The reason people say to wick for the last half of the jar is because everything can change in the last half, so really you want to have a safe candle. I hope this help and sorry if it doesnt make since I am really tired, off to bed.