No, don't leave any slack. I can't imagine how the author of the article can
possibly justify this.

As far as using chains, no. Don't ever use them. Carry your own tiedown
ropes if necessary. You can't get chains taut enough. A high wind will cause
the plane to yank on the chain until it runs out of slack and breaks.

I would bet that any Cessna (or any other plane) that has had a tiedown ring
break in a high wind was tied down improperly in the first place.

The plane should be tied down securely whether you expect high winds or not.
You could get an unexpected thunderstorm.