The oral LD-50 for KCL is on the order of 2.6 grams per kg of body weight for rats, so probably similar for other mammals, which means for a 70 kg mammal, it would need to eat 180 grams KCL to have a 50% chance of dying from it.
I feel safe taking 15-20 grams of it over the course of a day, in divided doses in my soup, with plenty of water inbetween and lots of pissing going on, and sodium intake, so as to let my system slowly adjust , absorb the amount of K it wants, then piss out the rest. Drinking pure water is a good thing