Nat
That's an interesting question.
I play a 67g shaft and I have made up wedges with it. The jury is out. It's pretty good on full swings but sometimes it feels too light around the green.
On one, i've added a strip of half-gram per inch lead tape to the full length of the shaft. So far, I like it.
Otherwise, I have two Cally wedges that came with heavier OEM graphite shafts. I love both of those. One is a Fuji 85T wedge shaft, and the other is some PX thing. Both test out very soft.
So I think the answer for me is a heavier but not stiffer graphite shaft. And maybe the lead tape will do the same thing.