Your talking about the Play Action belts, which are my favorite for charter fishing.
With belts you just have to try them on to find a shape that fits your body well. The braid ones are nice, but heavy. And for cows and giants, they are the way to go.
I have an old cheapy Fisherman brand that I have had for about 10years that is hollow and light (for carrying on the boat) and fits me well. I did just have to silcone back on the neoprene on the back, but still works well.