Glad I asked, because I was guessing that by "rational self-help" you meant something like "practical advice backed by deep theories" (e.g. How to Beat Procrastination or Explainers Shoot High; Aim Low), and by "working on the Art" you meant a subset of that which focused on self-help for improving rational thought in particular.

But the way you're using the terms, it sounds like "rational self-help" means anecdote-grounded other-optimizing, while "working on the Art" means "rationally-grounded advice for self-improvement, including but not limited to improving rational thought."