I was given 2 Callaway Great Big Bertha Heavenwoods. One has the Kuro Kage 50G Flex-R shaft and the other has a Bassara E52 x5ct Lite shaft. Can anyone give me some info on the differences(flex, weight, launch...) in the shafts and what each may be better for(ie. swing speed, spin, players ability). They will be used by me and my sons. We have a wide variety of ability and swing speeds and I'm just trying to see which shaft is better suited for whom. Since we don't play very often, I'd don't want to invest the $ to get all of us fitted at this time. Thanks.