Cracking accs

So I have a question if someone can help me with cracking I need to know how much interval I need and threads or what should I do. Alot of passwords and less usernames or less passwords and alot of usernames?

At least 20k usernames
about 3-10 Passwords
At least 10k Good proxies
No Interval
As much threads as your pc can handle

I have 12GB Ram and 500 bits up and down what do u prefer