Originally these schools were only for what was then called the Congregation Servant. They were held at Watchtower Farm, I think...The class ran for a full month, so those who quit their jobs or endured some other alleged hardship in order to attend the school were held in estimable honor before all the other slackers in attendance who might be wealthy enough to pay their own way. Later Assistant Congregation Servants were invited to the two week schools. After the elders arrangement went in effect, similar two week schools were held throughout the country. The schools were long on intimidation and some who were then elders came away from the school no longer serving as one. There were a number of pompous twits that I remember who were instructors, most old time CO's or DO's. One was Bruce Giffin a really rude man who didn't have much use for people.
The Davis you mention was most likely Randall Davis. He really thought a lot of himself in those days. Last I heard he left Bethel,but I don't know for certain.