This might be worth looking into.
The only reason against it is that I don't know anything about it, but I guess I could search for circuits how these Hall switches are used.
The issue with the reed switch is their odd characteristics, I will have to get the position down rather precisely to give the effect we want. We have a magnet swing by the switch and do not look for a solid on or off for a large arc of the magnet's motion, but we look for a rather brief 'blink'.
With a reed switch that means that the "sensitivity area" needs not to be solidly entered but only lightly crossed, mechanically this is a demanding task.
If the Hall sensors would give me any advantage in this I would wholeheartedly embrace that device. But how is the reliability of those??