There are many good places and good outfitters to hunt Stones with, in BC and the Yukon. The most important is the area and the 2nd most important is the quality of the guide. I outfitted Stones for over 10 years in the Cassiar Mtns of N. BC. We had a good area, but not fabulous. We were successful because we had great hunters and young/tough guides and no resident hunting pressure. We offered very few horseback hunts due to the remote and rough country. Most Stone outfitters are horseback oriented. A few offer backpack hunts. Some areas have little resident pressure and others have lots. I'd recommend booking a hunt with an outfitter you can relate too and one that has a hunting style compatible with your own. Most outfits don't take archery hunters, but some will. If you don't like horses, don't book a hunt with horseback oriented outfitters. Horses are necessary in many areas though due to the lack of lakes and airstrips. One of my favorite ways to hunt is to get to the hunting area with horses and then go hunting with backpack, while a wrangler looks after the horses. The biggest challenges with horseback hunting is that oftentimes, the hunters are not glassing at first or last light, because they have to ride during these times, to/from camp.
The biggest and darkest colored rams, in general, come from the East Slope of the Rocky Mountains in BC. These are the Halfway, Sikanni, Besa, Prophet, Muskwa, Tuchodi, Toad, Liard, Denetiah, Kechika and Turnagain River areas. The most well known areas are: Sikanni River Outfitters (Mike Hammett), Prophet Muskwa Outfitters (Olmstead), Big Nine/High and Wild (Thompkins), Tuchodi River Outfitters (Larry Warren), Stone Mountain (Leif Olsen), Folding/Terminus Outfitters (Drinkall), Muncho Lake Outfitters (Art Thompson) and Scoop Lake (Darwin Cary). The Cassiars, are located between the Coastal and Rocky Mountains and make up the North Central part of BC and in general also have dark rams, typically with smaller bases. These drainages would include the Stikine, Spatsizi, Dease, Upper Turnagain, Sheslay, Jennings River, Major Hart, Cassiar, Dall. The Major outfitters there are Spatsizi (Collingwoods), Upper Stikine (Now, North River Stone, Ron and Maria Nemetchek), Bradford and Company, BC Safaris (Keith Connors and Shane Black), Simpson Stone Sheep, Kinaskan Lake Outfitters (Creyke - this is the area with one archery only area - Todagin Mountain), Tahltan Outfitters (Jim Peterson and Carmen Nyuli), Golden Bear (Greg Williams), NW Ranching and Outfitting (Heidi Gutfrucht), McCowan's Sporting Adventures (Harry McCowan), Cassiar Stone Outfitters (Mike Kabanak), Kawdy Outfitting (Lancasters), The NW part of BC is where the Stones are a bit lighter, more like a Fannin. These areas would be Taku Safaris, Indian River Ranch and Jennings River Outfitters and they are located East of Atlin and near the Yukon. West of Atlin, tucked up against the Yukon border, the Sheep become true Dalls. The two Dall areas in BC are Moon Lake (Shane Buchanan) and Northwest Big Game Outfitters (Jack Goodwin). There are a couple other outfitters with stone sheep having only a couple tags, that I did not mention. Some of these area can be great; others are hit and miss.
In the Yukon, the Cassiar Mtns and the Pelly Mtns contain most of the Stone Sheep. These hunting areas would be Yukon Stone, Dueling Stone, Trophy Stone, Teslin River and MacMillan River. Some of the sheep in these area are also more like Fannin Sheep. The North West part of the YK has most of the lighter Fannins. These areas would be Reynold's Outfitting, Blackstone, Jensen Outfitters, Midnight Sun. Still, a lot of the sheep in these areas are pure Dalls too.
The most archery friendly areas/outfitters are Big Nine/High and Wild (Thompkins), Kinaskan Lake (Creyke), Yukon Stone (Russ Geisbrecht). There are other areas that have taken bowhunters, but in small numbers. The key for a bowhunter is good sheep densities and a willing and patient guide.
I didn't go out on a limb and say which outfitter is the "best" as each area/outfitter has its own strengths and weaknesses. It is really important that a hunter pick an outfitter's hunting style they'll be happy with. Patience is very important for stone sheep hunting. Make sure you and your guide are able to glass either in the early morning or evenings, as many stone sheep will live/sleep in the brush, making them very difficult to spot during the day. When asking for references, make sure to call hunters that have some experience under their belt and also from a hunter(s) that was unsuccessful.
I hope this information helps. There are lots of options out there for sure. Stone Sheep is probably my favorite all around animal to hunt. It is not overly difficult to shoot a ram; it is difficult to find a really big one. Good luck in your research.
Bryan