When your new to this site play whoever you want. You don't know how good u r yet so test yourself, soon enough u figure it out.
As for ratings; i play people around my level within say 200+ points no matter how many games they have played i do this, and I'm sure to get a good game most times. Sometimes i play players more then 200+ point so i make that unrated to challenge myself and allow them no risks if i do beat them. Other then these points i mentioned, don't take it to seriously, best win is just a once off great game and doesn't always reflect overall skill, where's average opponent stats is a little closer to showing u what they are capable of, once they have played 100+ games at least. Make sure you do examine their latest 5 games to gauge better how they are currently performing. That's my input anyway.
You seem to have a very structured system and it is interesting input. You are probably fairly unique in this however (I will now probably have a host of responses saying otherwise). I still do not think it changes my view even if there is only 200 points in it. My problem is that I have never beaten anyone higher than my highest ranking.
Many people's best wins are from when the opponent has to resign due to A) a having to leave the computer B) neglect to play a much lower rated player or C) other....