I'm using straight Ecosoya CB135 with CD wicks, and have worked out a combination that burns well and completely, great throw, not too hot and no mushrooming. But I get about 45+/- hours from an 11 oz. candle. I tried adding beeswax to slow the burn a little, but that made weird black spots in the melt pool and didn't seem to make a difference with the burn time. Are there any other additives that might help, or should I just be happy with this candle as-is? Thanks for any input!