How did I miss that cool write-up fishpaste, thanks for posting that!
Floating bread crust works on those sandvlei mullet or little very thin sardine bait I've also seen used by the locals. I used to catch them with little bread dough balls too. The bread crust you pinch the bottom half and take the hook bend in and around cleanly in the pinched section so the crust floats. Chum them up with little dough balls (size of a BB pellet) or bits of floating crust and leave your hooked crust floating amongst them. With the dough, once they are feeding on your chum balls cast out 3m or so(as far as you can) with a just small ball on the hook point and retrieve ever so slowly and they will jump on, key is the slow retrieve to keep it moving away from them which they cannot resist. The smaller ones like to hang around the mouth and the bigger ones are in the main body, around the island and caravan park channel and top canals. Have a can of koo mielies and a light rod with for the carp and a light spinning rod with a small plug handy for the leeries, good times to be had. I don't think livebaits are allowed anymore but topwater is boss I've learn't, me and a few mates used to do it as a regular jol. Seen lots of razor shad in the vlei in the past, used to nail the tails off my plastics while throwing for leeries so that could explain the one guys bite off. Also the local subsistance guys get a lot of those big springers off the island on the SE corner, you should go and sit with them how they do it and clean some rubbish up as it was always a mess haha.
And although I have eaten some of those big mullet out there in the past and they were tasty, I would not recommend it with the heavy metal contamination in those waters.
On a last note another thing to try would be what they do in UK with a small spinner and some type of worm on a tiny long shank single on thin wire behind. The flashing spinner gets them to swim behind as they do and then the see the worm, chomp their way up and hook themselves. Apparently..