Where I grew up, most of the fishing
boats had a piece of stainless rod through their wooden Sampson posts. They would wrap the chain around the post once or twice, then stick the rod through the center of a chain link, then go for another wrap or two around the post. I never saw one slip, ever. The rod diameter was probably about 3/8" (10mm) & probably protruded from the post about 2-3" (50-75mm). They sometimes had to pull up a little slack from the anchor
end to get the chain to come off the rod.
Another good option is a short piece of line with a snatch hook on it. Just hook to the chain up short, then cleat off the line.
If you have concerns about a hook on a snubber coming off of a chain while at anchor
, you may wish to wrap a lanyard around the opening of the hook so that the chain can't come out.