Oil switch/choke help.

[SunSoaked]

I'm looking to add an oil pressure switch in conjunction with the electric choke like the factory.
I see there are 1,2 & 3 terminal switches available.
I can't get a clear answer on which one I need because they don't list how they operate. I'm thinking the one wire closes the contacts with pressure and thus could be used on the ground side of the choke coil.
Or...use the 2 terminal version and use it on the hot side of the coil.
Anybody know the easiest way to do this? VetteVet?

[DoubleDubya]

The factory switches are two terminal. There should be a 12v supply wire from the fuse panel to the switch and then another from the switch to the choke. The choke is grounded so that completes the circuit when the oil pressure gets above about 5psi and closes the pressure switch.