Great Grandfather's brother's "designation" in [Kin]:-
Surely, a Great Grandfather's brother's "designation" in [Kin] should be Great Granduncle.
Surely, a Great Grandfather's sister's "designation" in [Kin] should be Great Granaunt.
or am I missing something!
Also:-
The choices on [kin] goes x3 x5 x7 [implying 2 "extra" generations for each step.]
In practice it seems to be x3 x4 x5 [1 "extra" generations for each step!]