A box of orange clay targets last a long time. Just drive over there and place a dozen or so in good spots.
For a bigger target just group a few. Even when they break you will still see them.
Also roll a few rocks to where they can be easily seen. Sun angle can be a problem so try to find different
spots for different times of the day. What youve found is just the tip of an iceberg you havent really been looking for.
Now you will be finding others. Good spot to be on opening day buck. The far hill could be better.