Do not rely on catenary from either chain or kellet to absorb shock. Use a
nylon snubber to do this.

Kellets are good at reducing your swing radius, and their functionality
really ends there. Put the weight of the kellet into the anchor instead, so
you have a larger anchor, and you will see a much better return on ultimate
holding power.

A good angle of pull on the anchor should be attained by the use of adequate
scope.

Well said, and as I pointed out, there's nothing like experience.