In my experience sheep hunting in not a low light affair... so a 77/80/85mm is not necessary. A 60/65mm spotting scope is lighter and easier to carry. The spotting scopes most I've seen guides use are of the "Alpha" variety with the Leica being the one I see most often. They also like the APO/HD/FL lenses in them. Not for the color correction, but for better definition in low light. I recently purchased a used Leica 62 APO with the 16x-46x variable eyepiece the size and weight are tolerable and the image clarity is wonderful. It's the angled model so looking up hill is a breeze. I carry a medium sized tripod and I use it for my binoculars as well as the spotting scope. You can find a lot more sheep with your binocular mounted on a tripod than by hand holding them. I like using quality 10x or higher binoculars for locating sheep, then use the spotting scope for judging the rams. Most of the time I find my eyepiece set on 30x. Hope this helps! Ovis_Chaser
P.S. The best advice I can give you is to get into the best shape of your life� Sheep hunting involves �getting up the mountain� and is physically and mentally demanding. Unless you work at a job that keeps you in shape, you�re not in �Sheep Shape�� being in shape is more important than any gear you take with you. O_C
