You may want to do a search for "Range finder" in a subject title. There have been bookoo threads about this over the past few years.
If you are not in a hurry , Leica is coming out with a CRF 1600 this fall. If it proves to be all it is said, and they do not increase the Beam devergence, it will be the ticket. If , if ,if, but if so, I predict a bunch of used Leica 1200 crf's and Swaro lasergudes for sale.
My advice for right now is Swaro laserguide or Leica 1200 CRF I carry both all the time. If you are mostly on flat ground, and small animals, I would definatly go with the Leica for the smaller beam and more pin point ranging. You will need to use it on a good rest, I like two sand bags to nestle it in to. Using a RF at long distance on flat ground with small targets is much like shooting a rifle. If it is not rested solid the results will not be as good.
This one was at 880 yards. Is this the terrain you speak of?