Fish and game was a big help to me last year early in the summer. I went in and met the Biologist for the area and he pulled out the count maps for the previous February. He was able to show me exactly where they saw sheep, gender and class of ram. So I would start with the Biologist for that GMU. Here's the bad news.. Fish and Game does not do species specific counts for Big Horn Sheep. The counts are done in conjunction with the elk counts, from a helicopter. Very hard to see sheep from a moving helicopter. So the counts will not be accurate in any sense of the word. Also, if there are no elk in Unit 42 they most likely have not done counts. It's possible that they combine sheep with some other trophy species like Pronghorns for counting ......not sure on this.
Do you have someone to hunt with? I live south of you between you and the GMU and would be interested in seeing this area. You've got to drive past my house to get where you are going. PM me if you think you might want the extra eyes and pack frame. I can carry my own food in and more then half my body weight on the way out
As a Taxidermist I look at hundreds of Whitetail Bucks every year. I know that I have seen many different ways people judge the size of racks on live deer. I think for the most part they all are pretty close. I'm going to give you some measurements that I have noticed being right on in just about every deer. We have used it in the last couple years and have only been off by about 5-6 inches. We do study the deer while bowhunting so we get a little more time to look at them....