I think putting 10% of your roll into the Step Challenge is a very bad idea. Yes, the payouts are good, but you are a ridiculous longshot to take that down. I think the Steps are much better for fun money, or money you feel like gambling on a longshot with... more like a lottery ticket than a way to increase one's bankroll.
Just my 2 cents.
P.S. You owe me 25 bucks