I'm 59 with a driver swing speed of 95 and just over 2 months ago I attached a 50g HZRDUS Smoke IM10 6.0 shaft to a Ping G400 LST 8.5 head and this has completely changed my game (for the better). However in my case I had already tried 50g HZRDUS Smoke CB 5.5 and 6.0 shafts (with this Ping head) and got disappointing results but I saw the HZRDUS Smoke IM10 6.0 shaft cheap on eBay so took a gamble. I didn't actually notice it was a 50g shaft but just bought as I had previously owned an IM10 6.0 60g driver shaft.
I can't put my recent improvement 100% down to the HZRDUS Smoke IM10 6.0 50g shaft as I am now having lessons every Monday afternoon and also changed the head weight to 21 g.