I got the same result: DEHK.
I’m not sure that there are no patterns in what works for self-taught architects, and if we were aiming to balance cost & likelihood of impossibility then I might look into that more (since I expect A,L,N to be the the cheapest options with a chance to work), but since we’re prioritizing impossibility I’ll stick with the architects with the competent mentors.
7% of the variance isn’t negligible. Just look at the pictures (Figure 1 in the paper):