A helpful reviewer in the US app store said the following about the default profiles' playing strength:
I'm an AGA 1d. After a couple of hours of playing 9x9 games, I was finally able to beat it at the default ("Fuego") setting without a handicap — but only once. My guess is that the default strength is at least 3d. I also tried playing against "Fuego (weak)," again without a handicap, and I was able to beat it most of the time, but not all the time. My guess is that it's about 2k. The app calls the "weak" setting a "1" and the default setting a "5", so I would tentatively say:
"1" = 2k = Fuego (weak)
"2" = 1k
"3" = 1d
"4" = 2d
"5" = 3d = Fuego
The information in these estimates should be added to the app in some way, for instance as added text to the default profiles' description.
A helpful reviewer in the US app store said the following about the default profiles' playing strength:
The information in these estimates should be added to the app in some way, for instance as added text to the default profiles' description.