Without actually burning a new jar all the way down, is there a formula to estimate hours of burn time? I am adding a new jar, 4.58" in diameter by 3" high, 3 wicks, soy wax, no color. The jar is a straight 25 oz. cylinder that holds approx. 18 ounces of wax. Have not ordered the jars yet and only have the one sample, so hate to burn in case I need it for more pictures. I know I will probably have to burn it, but, a girl can hope...... Thanks, Kate