We have tried a few waxes and prefer EcoSoya CB-135. It easily melts (double boiler or microwave), and has very little shrinkage. Clean up from spills or used candles is just soap and warm water.
Click the image to the right to get some for yourself. We have many Mason jar candles in our preps for emergency light, as well as a hanging Mason jar candle in every room. During the last power outage, we burned some of our candles for days, yet they were not even 1/3rd burned down.