Your outfitter is in Marken. I am not that familiar with the area. I know there are a TON of blesbok at a concession named Buffelspoor just north of Thabazimbi and next to the Marakele National Park. Still, it is probably a 2 hour drive each way and the last few miles of the road to the concession is not the worst road in the world, but it is the worst road I have ever personally been on. Still, there are likely to be concessions around your outfitter that have a lot of animals that you are looking for if you explain how important those are for you.
On the other side, unless you have a big hole on a checklist you are wanting to complete, it is often best to just take what Africa offers. Sometimes an animal of opportunity is a great thing.
Now, I was just in South Africa this last August. It was the worst blind hunting I have had there for no other reason than the weather. They had a lot of rain so there was plenty to eat everywhere and lots of water standing in various places that kept a lot of animals away from watering holes. Also, a cold front came in and the animals don't move around as much when it is windy. It actually was snowing or supposed to snow in some parts of the country when I was there (I think in Jeffreys' Bay). Still, I got 6 animals in 7 days.
I would think all those animals would be high probability as long as your outfitter has a decent population on their property and they have trail cameras at the waterholes to see where animals are coming in and when. I cannot imagine any successful bow hunting outfit that wouldn't be doing that so it will boil down to how big their herds are and how many trophy animals are left by the time you get there in that season.
Good luck!