K = 20, Kademlia, Probabilistic analysis?, Experiments?

I was wondering if I can get to know how that particular K value has been chosen, so as to increase the probability of atleast 1 out of 20 advertisement points are available during churn.
Or Any pointers for that experiment would help. I can do the experiment myself.

Naive would be

Failed choose 20 / Network choose 20 ?
is it wrong?