I mean, it's complicated to gauge Tserriednich. His aura should be as strong as Meruem by the end of his training. All that's left is how he'll use his nen and what hatsu he'll have. It's not even confirmed that King Crimson is his hatsu, because you would need to make a "contract" with the nen gods to have restrictions on it. Something he hasn't done. And to be honest, the whole thing about making a contract with nen should be explained better. Like, Chrollo seems to have done a newer contract but it's not explained how.
I believe Hisoka's way to scale nen users is only based on "aura". Aura can be measured and compared. Hatsu cannot really be compared with numbers imo.