The idea of weight being a deciding factor seems odd to me. The fit and function for the type of hunting you do should be what you decide on. I would bet if someone put two identical packs down next to each other loaded at 70 pounds and 75 pounds, most people couldn't tell the difference. So gross weight of the pack before it being loaded shouldn't be a deal breaker. A pack that fits you well and keeps the weight close to your body will carry weight better. And when you get a pack like that 5 pounds of difference packing game out you will never notice.
And on a side note Chesapeake, I have never seen a 4500 in the 7 pound category. I have made every modification possible to my 4500 and it is still at 8 pounds 3 ounces. So if yours truly weighs 7 pounds share your secret so we can get them down to that weight also.
The OX is just another tool in your tool box to fit a particular type of hunting. There is no one pack that does everything that I know of, unless you do just one type of hunting.
