There is no ProLaunch Blue 58g A flex any more and no NV A flex that is 47 grams. However, I think either the ProLaunch 45 A flex, the NVS 45 A flex or the NVS 55 A flex would be the ones to consider. As we get older (and I speak from experience) and loose some of our speed, the one thing we need to try to do is swing the lightest overall weight club we can control and play the longest length we can control. Those two things, along with having the right loft angle to get the ball launched properly, are the best things we can do. all three of those shafts have similar playing profiles and could help. I listed the one 55 gram in case you wanted a little more weight, but you should consider the 45 gram options, I believe. Hope this helps.
Britt Lindsey