Great point Kerven! If the candle wick is producing a large flame it's most likely the wax quality since the wick itself shouldn't change it's own burning quality in different jars, because it should only affect the melt pool size. I didn't think of this before!
Maybe the wax from California Candle Supply's is just not good on its own, not is it good when you only add a small amount of soy. Even though they told me their wax should work without blending, I'm finding that impossible.