I don’t understand how this tactic gives any advantage.
I don’t know either, I’ve never seen it used.
As I understand it the bill will be brought to the floor as a collection of 22 amendments. Once the cloture vote is passed, Harry will "shoot the clay pigeon" and break the bill into 22 separate amendments and force a vote on each one. The idea is to take up the 30 hours of debate voting on each individual piece of the bill so no other new amendments have a chance to be brought.
Something like that at any rate. The idea is to use up the debate time so no opposition can be heard.