I know Yuri Arcurs has hit 1000 downloads a day with SS. Probably not every day though. Look at his portfolio and you can see why but he does have a few people working for him.
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Andersr is probably not far behind.
I am sure you would make a lot more if you uploaded to more than 5 sites. In another forum I read that Yuri Arcurs makes over $400 a month from Crestock. That is my 8th best earning site.
People moan about the smaller sites but they still have earnings potential with a good portfolio like yours.