I don't agree with:

", i.e. when the climb
starts to flatten, you should release immediately if you're even slightly
above the placarded max winch speed. "

I do agree of course that exceeding the placarded limit is not a problem earlier in the launch when the cable is pulling the glider more forward than down, but that the load on the glider (and the weak link) is more critical towards the end of the launch. However, rather than releasing, I think that safety (and not breaking the weak link) can be achieved by relaxing the back pressure.

The correct weak link should prevent any glider from suffering structural failure, and probably does. But has anyone ever heard of any accident caused by exceeding a placarded maximum launch speed?