To be honest, I think that sort of thing depends much on your actual girth. I've seen big dudes use such setups quite efficiently: for me, they'd basically make me twice as wide before they even carried much. From observing other photographers and myself, well, the tendency is for most big people (yeah, I mean guys) to kind of park somewhere and sometimes have either what they need right on their person, or go for zoomage. If they need to move, they get up kind of a head of steam and push through. (Often pushing me, actually, but it didn't take me long to figure out how to make use of that.
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Someone my size would go for whatever's slipperiest in crowds and such, move a lot, wedge yourself in somewhere, etc. There, shoulder-bags and stuff you can maneuver, rather than have stuck to you in a fixed place is better.
My general impression is that the smaller you are, the more diminishing returns there are about a belt setup. If I want to carry enough stuff that a belt kit would be necessary, there's probably not enough space on a belt that would fit me, without needing to save space for a bag anyway.
One thing you could do with your 7MDH, (this is what I sometimes end up doing,)is learn to be comfortable with it actually slung courier style, (it'll ride high up but you can still get at stuff) as well as off one shoulder. What I do there is when I set a conventional bag's strap, is have it sit so my fingernails can brush the bottom of the bag's interior when it's worn off the shoulder. If the shoulder gets tired, I just shift the bag over my head, but wear on the same side. That way I can get at things either way.
Since you look to be of moderate size from your avi, I think what I'd do is measure how much I wanted to be carrying, (a few inches of waistline adds up to a lens case,) and just how big an affair it might end up being. I think if I were looking for a system like that, say for concerts, what I'd want would be maybe a marsupial-kinda camera holster, maybe a lens/flash case, and something for film/batteries/memory. What I used to do for 'expendables' and any stray small lenses would be to wear a man's blazer with big pockets: spent/shot batteries/film on one side, fresh on the other. A bag would manage what I wasn't slinging. Often what I'd do was come to a shoot with two bags, and cache one which would be just about empty by the time I was set up.