re suitable hall switch
Am I looking for the correct type of hall switch?

I think I may be closer with this
UGN3177UA
http://www.ortodoxism.ro/datasheets/...stems/3175.pdf

These Hall-effect latches are temperature-stable and stress-resistant
sensors especially suited for electronic commutation in brushless dc
motors using multipole ring magnets. Each device includes a voltage
regulator, quadratic Hall voltage generator, temperature compensation
circuit, signal amplifier, Schmitt trigger, and an open-collector output on
a single silicon chip. The on-board regulator permits operation with
supply voltages of 4.5 volts to 18 volts. The switch output can sink
10 mA. With suitable output pull up, they can be used directly with
bipolar or MOS logic circuits.

These are available for resonable price in Australia ~AUS$5
cheers Jeff