Is is a very thorough and well explained article. I guess what I got out of this for my work is that I’ll put a “drainage layer” in most of my taller pots and leave it out of my most of my shorter pots.
Thank you for this, it was very in depth and even confirmed my long standing lack of confidence in the Tesco cat litter mix I am trying. I didn't realise it was as well known as this.