I have no problem carrying binoculars in a harness while using the gun bearer. My wife made the binoc harness for me - the harness closely resembles a FHF harness.
However, when using the gun bearer my rifle barrel sticks up very close to my face, so I have to be very careful when actively using binoculars. Don't want to smack my nice glass against the muzzle. It's possible I just need to adjust the gun bearer so the muzzle isn't so close to my face. Admittedly I haven't tried...
It's not typically an issue for me because I prefer to carry the rifle slung over my shoulder while actually hunting vs. hiking in to camp or packing a load of meat.
So I got my KU5200 and Savage Lightweight out and started toying with the gun bearer. Was quickly able to make the gun barrel position both worse and better with some adjustments. In the best position, I am still not entirely comfortable glassing, and would not let a good pair of binoculars dangle from a neck strap while using a gun bearer - too much risk of banging glass against metal. Using a padded FHF-type case I think the gun bearer is a great solution for carrying a rifle while hauling a heavy load. This setup allows you to use trekking poles while packing your gear and/or meat.
But I will probably not actively glass while using the gun bearer. Your mileage may vary.
You can Google "Kifaru gun bearer" and click "Images" and see several good pictures of gun bearers in action. Should give you a good idea...
After buying my gen one Late Season with a gunbearer I rarely carry my rifle any other way. I run a Cabelas/Crooked horn bino harness and have no problems glassing with rifle mounted. Just adjust the bearer so the barrel is in front of your shoulder, not your face. Try running the bearer backwards, so the vertical strap is on the outside of the rifle butt(hope Im making sense here) if you cant get it out of your face.