Good Rule of Thumb: Don't use somebody elses chart.
2nd Good Rule of Thumb: Don't rely on any chart completely.
Charts are a good starting place, but they do not take into account all variables. It's always better to go with a too stiff arrow. It's relatively easy to weaken it's flight.
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It wasn't something we really discussed, but I can tell you that the only time we really reccomend someone shoot feathers is when they're shooting a traditional style bow or are a new archer shooting a prong style rest.
I'd love to know the reason why. In my opinion feathers can't be beat. Maybe it's because vanes have to be replaced so often - more money for the shop.