User blog comment:PsiCubed2/For Newbies (and Veterans too): The Great Scale of Googology/@comment-32876686-20171216155134

This is a useful idea, but if you plan on including uncomputable functions I think you may need more than a 100 Psi levels, (unless you decide to include fractional levels like Nayuta Ito mentioned).

It also reminds me of the Dewey Decimal System, but for the number line.