Having two dogs, whether adjacent or together will limit bored barking by quite a bit in my opinion.
I think when the barking happens it is mostly with comings and goings. The dogs WILL bark when you get home. So? As long as you go out and get the dogs before they become a nuisance no problem. The dogs will also bark when your neighbors come within their view, like when they decide to play a volley ball game in their back yard.
A privacy fence will cut down a lot of barking like that, but if people are making plenty of noise that is unusual, well, the dogs will probably bark. They are, afterall guard dogs.
There are dogs that bark becuase they are bored and lonely. I do not see that as a problem for you, especially with two. Since mine are on concrete, I have things in my kennels to lie on to get them off of the concrete. I keep a dog house in there for them to have shelter in. And I have a large shelter in their dog house.
I put a tarp along the side to block some of the view if I have some that dislike others or if I just want more protection from the sun. Sun screens on top.
They are really quite quiet except coming and going.
This is how I set mine up. Two types of shelters, one is more open and doesn't do much for rain, but the dogs cannot jump up on them so it is good for the pups. They have their houses inside.
The other type is like a 4x8 box with a roof and three sides. One 8 foot side is open and holds the cot. They are very sheltered and the dogs love to stand and lie on top of them as well. They have a floor -- marine plywood on two by fours -- works very good for me.