Same here 1/4 channel ... welded 2 d-rings to the front...
Mike and bruce made there's ....
I don't recommend flat steel, the channels give it strength....
two plates 8"x34"x.25", so use 1/4" steel. The pieces cut from the vertical plate are used for gussetts, so it's strong with little waste.
A buddy of mine made one to mount his Warn 9.5ti, using 1/4" c channel turned upside down. He welded angle iron in each end to sit on the frame and bolt underneath the towhooks.