Brian, just remember that you'll either have to make it in sections to assemble at the bait site, or small enough so you can pick it up and move it with a tractor to where you want to place it. I'm unsure whether your tractor could place something that size where the trap was placed. It'll probably pick it up easily, but moving it down the dam face might be a different story.
As for corn, when I'm feeding the deer here to get pictures of what's around, I'll go thru about 8 to 10# per day...... Can't do that and hunt the same area tho. The deer get into a habit of coming, and noise doesn't seem to bother them. They'll show up 10 minutes after the tractor goes by.
