I just got the Primos arm and it seems to work well. Haven't used it in a hunting situation yet but hooked up to a tree in the yard it held up my Sony 2100 with no problems.
I don't see any horizontal adjustment on that arm, there is obviously vertical adjustment, but how do you handle a crooked tree?????Get ahold of Antlerhog as he is making a very sturdy custom arm. It will hold any camera you are willing to pack into the woods. And it won't break the bank. Best arm available and affordable.