The correct brackets and attaching pieces you are looking for can be viewed on ebay at 220763239513. These brackets mount to the bumper brackets and the long bolts protrude through the splash pan. The dome shaped pieces sit on the pan and support the light.
One place Kurt in NJ didn't mention, on top of the frame rail right about where the left cowl sits. In other words, three places on the left frame rail and on the transmission case.