I wanted to use the strongest magnets given the constraints of the HSW system. I found these magnets (unfortunately they use imperial units):
Modified the insert to accomodate as above. This allows the magnet to sit flush with the honeycomb wall when mounted against the refrigerator panel. Allows for press-fit with tolerance. Hole on reverse side allows for pushing the magnet out should you wish to recover it.
The author remixed this model.