Maize has an extract potential of about 40 points per pound per gallon. At 75% efficiency, that would mean you would get about 30 pppg.
Corn sugar has a potential of 44 pppg and you will get 100% of this, so you should replace each pound of maize with 30/44 pounds of corn sugar, or about 11 oz.
There are only 10 types of people in this world. Those that understand binary, and those that don't.