If you are really culling, or the action is fast, furious and dangerous, then take off the lower belt (if it will still hold your pants up) and put the culling belt over everything.
If the lower belt is needed to hold your pants up, then wear it, but take off all the accessories.
Unless you are the PH, tracker, or skinner, your job is to put as many bullets as possible exactly where they need to be and nothing else.
If you are in the normal situation of a client hunting with a PH for DG, the culling belt is nothing more than a fashion accessory, IMO.
I have one that someone gave me for a .470 NE.
I like owning it and I appreciate it. But, I wouldn't take it out of my backpack unless some crazy stuff was about to go down.
If you are going to use it, then practice reloading from it.