A Burris Landmark 15-45 60mm scope will suffice for what you are looking for. a friend has one, it is clear through the field of view.
I have shot across the course for over 20 years now. I own Unertl, Leupold, Kowa and Pentax spotting scopes. And a cheap Barasika. The good scopes are as good as you can get within reason.
Regardless of scope, you cannot see through mirage. Two hundred yards is about the limit for reliable spotting of bullet holes. Even then, if the range has a lot of mirage, you are not going to see your bullet holes.
It takes an exceptionally clear range, such as Camp Perry, which is by a lake, to see bullet holes at 300 yards. Occasionally I can see 30 caliber holes on the 300 yard range at Perry.
Someone brought out a Russian naval scope to the 1000 yard range at Perry. This thing was in a turret, the lenses were at least 14 inches. Though the image was exceptionally clear, you still could not see bullet holes through the mirage.