Scotty,
The majority of the schools in the league probably have between 125 - 150 kids on the opening camp roster. However, by the end of camp a more realistic number for most schools, excluding MUC, ONU, and BW the roster is probably around 100. During camp and when depth charts start to work themselves out, alot of your so called high school standouts cannot stand being number 2 or 3 on the depth chart and some leave. Like mentioned before, grades and financial aid also have a way of taking some players away. IMO, the more players you have the better. One thing that really keeps players around in the OAC is the JV schedule, the larger your squad, the more JV games you can play. It allows players to gain experience and wait for their shot on Saturdays. Also, with more players, it allows a team to divide up and have some pretty good players running the "scout teams" for the week. Which in turn allows the varsity to get a better handle of the plays and what not for the upcoming game. There are ways each individual team has of coaching that many players. Most often the team divides into the different positions, 5-20 players per coach depending on position, for the bulk of practice and come together at the end for a full team practice, sometimes running two units at the same time.
