Scrapes for me are nice to see but have never produced great results. I also have camtrakker them and found the activity to be at night. Now on the flip side of this is rublines where I have had succes over. I generally setup on the route that leads to the rubline from bedding or food, not right on top of the rubline. You can determine when the buck is making the rubs by the side he is hitting, if he is hitting it from bed to food, then sitting their in the evening is your bet, vice versa for the opposite side. However the trick to knowing which is which is scouting and finding where they call home...good luck!