Whether one has one, two or three kidneys should not be of importance regarding doing this cleanse.
The number you have is the number that gets cleansed.
As regards to what you are eliminating, you should be only eliminating what you could consider "butt pee" after the second day.
If no "butt pee" is being eliminated then there is a possibility that intense colon cleansing could be in order. But not very common.
That would be someone whose digestive tract is extremely cluttered up. That could only come about from a longterm bad diet.