Sounds about right to me, at least for non-critical anchoring.
If you were planning on overnighting through heavy weather or something like that, I'd kick it up a size or so.
In either case, a decent amount of chain (somewhere around the length of the boat, depending on chain size), and about a 3:1 scope (line:depth) should keep you in place in just about any kind of normal conditions.
Danforth's aren't particularly reliable in hard mud or grassy bottoms, so if you have a lot of that around, you may want to get another style of hook...
jky
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