Incrimental. There is probubly no way you can clear it all on NL10. Unless your playing like 16 hours a day. NL20 makes it possible to clear playing 5~ hours a day 4-5 tabling.
The bonus is released $10 at a time every 650 MCPs. 6 tabling FR NL20 you gain about 60-80 per hour. 6 Table SH NL 20 you get about 70-90 per hour. It more than doubles if you go to NL 50.
The bonus is considered "Hard" for someone that doesn't grind, but if you like grinding its rather easy. I think the bonus is only good for 2 months though, not three.
Crazy part for me is, when I signed up they gave me a PS bonus the next day which gave me another 200 bonus on top of that. So 800 dollars to clear, which meant I need 52k MCP to clear the whole bonus. With just over a month left I'm now on NL50 with 27k of the bonus to clear, so I should be ok.