Agreed. Weak dollar is an informal policy and relatively easy to achieve with just jawboning.

Also, while touting a strong dollar policy, they’ve actually implemented a weak dollar policy. Since the public generally doesn’t chart the dollar, they’re not aware of this.

One week later, and the dollar is at the black line. Does it usually plummet or gradually decrease?

It can vary. But it's usually gradual but can be fairly consistent. The central bank doesn't want the purchasing power of people's dollars to drop too quickly.