Hi, I'm new to candlemaking. I've only been at it since May. I just switched from using tins to using mason jars. I use 464 wax and now that I'm using the jars I'm getting tunneling around the wick, sinkholes and cracks in the tops of my candles. I never had this problem with the tins. I had a nice smooth finish. I've tried pouring at a higher temperature and warming the jars. I'm out of ideas. Any advice? It's fixable with a heat gun but it ruins the smooth finish.