I use a quality 60x spotting scope for viewing targets @ 400yds. Beyond that, my buddy bought one of the remote cameras that is set up near the target and sends an image back to your phone, tablet, or laptop. I've never seen anyone use a drone. It could certainly present some problems if there are multiple shooters on the line.
DJI MIni has served me well. Biggest issue you'll contend with in smaller drones is battery life. It literally takes a good 3-5 minutes to get it up in the air. Most Mini's have AT MOST 15 minutes of flight time. So if you are wanting to watch and shoot you'll stress on battery life. If you shoot, fly down, then return. You'll be fine.