The sha1 hash for 64test64xa is 6779c53432b8badf049bb9d8924a5785dd887243 which is 41 characters only using hexadecimal, 10digits and 6letters. But how long it would be if it was using the whole 26 letters in the latin alphabet? What if it also differentiated between UPPER and lower cases?
It gets subtle when you consider Unicode. But you said latin alphabet, so you can look at just the UTF-8 section of this table, and assume 1byte = 1letter.
https://github.com/qntm/base32768#base32768
HTH
I think we should consider Unicode, I want hashes that look like
lau52gj🍀pr18e🍅