This "problem" has been solved long ago by Via Ferrata kit where using a simple sling between the cable and your harness is most definitely not recommended.

If you are going to use climbing equipment on Broad Stand then you need someone to belay and something to belay off. There are wires (and cams?) above the top of the second step so all that is needed is someone to place these and throw a length of rope down and the contender (and others) can tie this round their waist and get assurance on the exposed awkward parts. If that first person needs to protect themselves as they get to the top of the hard bit then they can be belayed as normal - if you come off the hard bit then even with gear in place you are going to swing in to the corner and either hit the platform or the far wall, it's more to stop you falling down and left.

Obviously if you are setting up the belay and ropes then it's best done in advance of the contender getting there to save time.

In dry conditions I'd even consider just setting up a handline fixed top and bottom and have those using it clip in with a sling - again you aren't preventing them hitting the ledges only from going over the edge.