This is just my 2.5 cents worth. I think a lot of people these days get way to wrapped up in what there arrow weigh, how fast there bow is, ect ect. If you choose a good quality arrow, Axis or FMJ, or what ever your budget will allow, all that is needed is to make sure the spine is correct for your bow, and that you put as much time into tunning, and being able to shooot your BH'ed arrow in all conditions, so that you know your effective range. The axis is a good arrow. It is a very tough arrow, and will be perfect to shoot, or it will be broken. No guess work. The FMJ's are a little bit straighter, and hit a lot harder, but they can be bent, and cost more. Both are great arrows.
More importantly, make sure your bow is timed correct, and BH tune your bow as best you can. Make sure you practice your hard uphill, and downhill shots. Shoot in to a croos wind. Try to get good at estimating yardage on flat grond, and at angles, (this is kind of a lost art) you may not have time to range your sheep if a quick shot presents it's self. Once you get your bow and BH set up shooting good, throw your pack on with weight in it, do a 50-100 yd run, 25 push ups, and try to get one good shot off with a BH. This will simulate the way you will probably feel when you get your shot, and we all hope that you do. Once you can do this, back that target up more. Chances are your first shot, might be your only shot. Your heart will be pumpin, legs and back will not be happy with you because of all the hiking you are going to be doing. Like I said this is JMO. Hope it helps, and good luck. If you get a chance to go scouting, post those bad boys. A lot of us will be living vicariously through you.