Maybe the following is an idea. Draw up a contract in whihc you commit to give away 90 percent of the post taxes winnings to Tzedakos all over the world. Designate percentages for Yeshivos, Chesed organizations, yechidim etc. WRITE IT OUT> Sign it in fornt of 2 witnesses, give then copies, tell your kids you wrote such a contract so you are diminishing g the chances of the Yetzer orah creeping in. Then buy it and say Tehillim that the mosdos need you to win.
I’m not sure I get this. Hashem doesn’t need your help. Of course, if you become wealthy, you should give a lot of tzeddah (if I may disagree with Uncle Moishy) but I don’t get the making a deal with Hashem part.