Personally I would say use ghost+5b when you need highest protection, and gremlin for average hunting that requires something decent. Gremlin is more efficient than ghost per damage given. I do not think you should say that higher armor will bring you more profits as chances are it will not, but instead picture it as if you hunt something already or you need the extra survival rating, then use them to gain that. After all deaths will cost you when you are trying to kill a mob, these 5b's will make a large reduction in that cost. For those mobs you hunt that kill you moderately often, you will lose less due to deaths.