Hi Chriss,
Thanks for sharing. Although many studies have included different (all important) aspects in relation to this particular topic, most have often failed to do it in an integral way. In times where we boast about the powerful tools we have created, modelling around this topic has to be improved.

Critical reviews remind us that knowledge isn't set in stone. We, practitioner professionals, often overlook this.

Here's a link to an article some of us at the University of South Florida wrote on why latrine setback distances should not be considered a one-size-fits-all methodology.
iwaponline.com/washdev/article/13/10/833/97930
We know we aren't the first ones to understand this underlying problem, but, to our knowledge, we are the first ones to look at how these guidelines developed and what field papers they use as their reason for a given distance. We hope you find this information useful.