I am curious as to what sized bit you used to pin the wrist? I will likely need to run out and grab a new drill bit, and want to make sure I have one small enough.
Good question, but I'm not sure. I just have a pack of them and it doesn't say on them what size they are. But I pin all my joints using paper clips as the supporting pin. So basically a bit that is about the width of a paper clip is what I used.
Greenstuff as buffer can work, but I find that to not be a very strong bond when the connection point is so tiny, since you're only getting a tiny bit of green stuff in there too. With something like Sven's wrist, the smallest bit of pressure on the tip of the spear during transit is still likely to snap the wrist joint if it isn't pinned, I think.