For anyone else looking into potassium chloride, I'd like to add some research conducted by the University of Tennesee.
https://trace.tennessee.edu/utk_gradthes/7387/In short:
They made three versions of sauerkraut; one with only regular salt (Sodium Chloride), one with only potasium salt (Potassium Chloride), and one with a premade mix of sodium and potassium salts (Morton Lite Salt, the package says 50% less sodium so I am going to guess it is about a 1:1 ratio. This is just a guess. Please correct me if you know otherwise.). The study tested microbial growth and flavor.
"Total and lactic microbial counts for the potassium chloride and Lite Salt treatments were found to be higher than counts for the sodium chloride treatments."
So, potassium salt seems to boost microbial growth.
"Sensory evaluation using an untrained consumer-type panel showed kraut prepared with Lite Salt compared favorably to kraut prepared with sodium chloride"
So, potassium salt makes good tasting kraut when mixed with sodium salt.
"Sauerkraut prepared with potassium chloride was rated lower than the other two treatments due to its bitter, metallic aftertaste."
So, don't use potassium salt by it's self.