I've always thought that green speeds shouldn't be tier specific, but based on day to day play or even round to round.
In the thought of being realistic, on the real course it doesn't matter who is playing, the conditions are what the conditions are.
Get to the first green and find out what the green speed is for that round. It would give more use to the practice rounds for players to learn all green speeds. This way, no tier should have to worry about playing with any other tier because of a faster green speed than they are accustomed to.