Years ago I went with shoulder suspender harness weight systems and have no reason to go back to weight belts. I basically have about 2/3 of my weight in the harness, and trim depending on suits, gear, etc into clipped on rig pockets. Just about everything is ditchable if desired, but in stages. Harness can be emptied, or with quick release on shoulder and waist, can even come out from under rig. I stopped using the crotch straps about 25 yrs ago. I dive harness with wet suits, and drysuits. As I have gotten older I have "packaged" the weight so that I don't kill myself hauling out an all inclusive package. Ever put a SS BP rig, doubles, trim weights, double regs, battery cannister, etc., on a scales?
For smaller boats, and inflatables, I roll out of the rig (with some air in it), and without all of the weight in the harness float on surface, exit, and pull rig in after. Also frequently don rigs in water. Of course this practice usually isn't done from charter boats, etc., rather from one's own boats.