User blog comment:Deedlit11/Ordinal Notations V: Up to a weakly Mahlo cardinal/@comment-11227630-20160601045613/@comment-5529393-20160601112136

Yes, that should be $$\eta$$. Thanks for these corrections, Hyp Cos and Emlightened, I really appreciate it.

The $$\chi_\alpha(\beta)$$ in the other notation should get you an inaccessible hierarchy; remember that $$\pi$$ is restricted to regular ordinals!