[cheesecakegood]

I think the book Superlearning just gives the simple rule that you should spend 10% of your budgeted time on meta concerns (what to learn, what order, what strategies to use, etc) and that’s always seemed a sensible, good-enough default that takes away the doubt. Knowing how deep to go is, as you point out, only half the battle unfortunately, but the rule helped me at least.