I test my candles by pouring half way up the jar. I tested for months and months and couldn't figure anything out and finally attempted this method. Using the 16 oz. LM Mason jars and CDN wicks, I have been able to properly wick scents using CDN sizes 12-16. I prefer to err on the side of underwicking rather than overwicking. I always have a bit of residue no matter what, even if I intentionally make a candle a small flame thrower just to see if all the hang up disappears. If my jar is too hot at the bottom then I pull the wick and test with a size smaller. I randomly test full candles and have yet to find one that was a problem. Mason jars are denser than the regular glass candle containers (except maybe an apothecary jar), in my view, so maybe that has something to do with the success of my testing method. But then, as you all know, there's always tomorrow and a new dilemna.