It seems pretty simple to me. Rubs and scrapes are good indicators of whats BEEN in the area, doesn't necessarily mean he's still there, especially if he's getting antsy for some action. In my experience, the best chance of catching that big boy is to just hunt where the does are. Feeding areas, bedding areas, travel routes, etc. The bucks know where all those places are, and will be checking them, and if you have some does around, even better, live bait! Hunting does is the best way to hunt bucks.