I just don't understand how you can use a RRD 47 or even a 50 in a Palm wax 3" diameter pillar, Would someone explain it ? Andy Rule of thumb for burn is 1 hr. per 1" diameter of candle. Most caution labels for candles that I have read say not to burn longer than 3 hrs. Granted, when I'm testing I will power burn one because there are people that will exceed the 3 hrs. When dealing with the palm, one of the reasons that wicking is tricky is because if you get the perfect burn for 3 hrs. then you will for sure have a blowout if you burn it longer. If you have the wicking perfect for those 8 hr power burns then burning it correctly will leave too large of a shell. This was the biggest problem I had when trying to wick the 2" palm. I try to find the size that wont blowout and yet doesn't leave a large shell. If you are wicking all your pillars for 8 hr. burns then they will be underwicked when only burning a couple of hours at a time.