My personal preference is only one gun belt. Im a bigger guy, so my waist can accommodate more things. I'm left handed and wear the buckle on the back of my left hip, out of the way of the pistol holster.
I carry: 2 rifle reloads, minimum of 6 magazine pouches (4 mags for the stage, 2 Barneys)and 6 shotgun (just in case I forget to load the shotgun...). I use pouches with snaps on them, so I can add and subtract mag pouches as needed for various stages.
People with smaller figures, usually need 2 belts but there's also a lot of people that just use the same shotgun belt they use in cowboy.