I'm using the Mako rubber belt with the uncoated Tinman weights, and find it perfect for scuba. The Mako belt prevents any slippage when worn over my Fusion drysuit. Whereas my fabric pocketed weight belt was constantly slipping on the slick Fusion suit even with a depth-compensating buckle.
I'm wearing 16# of Tinman weights, four blocks on each side, no weights in the back. I wanted the back free of weights to avoid hitting the backplate and to provide more rubber in contact with my suit. The weights measure 3"h x 1.25"d x 1.5"w, and they can fit together almost touching each other on the belt. So a block of 4 is only 6.5" wide over each hip. Each weight extends 1/2" above and below the belt, and I have noticed no interference anywhere with other equipment.
The squeeze feature of the weights works beautifully and the weights can shifted around very quickly and easily and never move once located.
The tail of the belt has to be left long enough to easily grip when you want to release the belt, so the tail is longer than with a traditional buckle release. I just tuck the loose tail back under the belt which leaves a loop to grab.
No complaints at all with the Mako setup. Works perfectly with my Fusion drysuit and BP&W. I've tried a few weight belts over the years and this is my favorite by far.