Wouldn't all this just be easier to use the average score of the players each tee or layout is intended for? If the SSA of a Gold course is 72 then the pars on the holes should equal 72. The same for White tees. If 72 on the white tees are a 900 rated round then the White or Am par should total up to 72. It's not that hard to take the average score for just the golfers the tees were intended for and either adjust the par or the hole some how.
Par isn't an average score. That isn't the way it works. Course pars are a reflection of how it plays. A par 54 course should be one where every "green" is reachable from the tee for the level of player it was designed for, and if the par is 72, then you shouldn't expect to reach many of the baskets with your drive. Whether the average is par or not depends on how tough the course is for the players it was designed for.