As for your next milestone, it can happen for you, if you keep fighting a lot and get familiar with your fighters, you will easily be in the top 500 in no time.
I was very close to making the top 10 managers last week. I was ranked 11th through some fluke of lucky wins against tough opponents and some favorable matchups for my fighters for the whole month of april. I think i was 18-1 for april. Anyway, my next fight didn't go in my favor and I am sure I'll never be that close to getting into the top 10 again, but i'll be damned if that wasn't exciting! Looking at some of the other top 100 managers I have no idea what I am doing in the top 100.