I have rarely seen more than a 2-4 point difference with fat shafts and that was only when 12's were in play.Fat shafts advantage is only the difference between the skinny shaft and fat shaft divided by 2.In most cases,this is less than a 1/32 of an inch.

For me it was an advantage staying with skinny shafts due to shooting in the open class where 45 yard shots were common and considering I was using a low poundage setup,my groups were much tighter at distance so skinny shafts were better.That being said,if I had more energy,I would definately take advantage of the fat shaft.