MSA Engine Kill Switch - wiring options?

Today I fitted an appropriate battery isolator switch which incorporates an engine kill switch to my Jimny (1999, Spanish Built model).

Normally you would just wire the kill switch in line with the coil - but with an electronic distributor less ignition system, it's not quite so simple!

Is there a preferred way of wiring this? The options that immediately occur to me are:
Kill power to injectors (by switching off common negative)
Kill power to ECU - the question is where?

Any thoughts?

Si

If the pump in the tank is high pressure & feeds the injectors directly, then switching it off would kill the engine immediately. If there is a secondary high pressure pump - then not. I'm afraid I don't have much of a handle on the Suzuki engine configuration!

Si

Have it as a battery kill switch. That turns the ECU of and turns the engine off. Probably not the best way to do it but it works.

The one I'm stuck on is the non return valve on the breath of the fuel tank. Does it even have a breather on there?

Just disconnecting the battery is unreliable because the Alternator can generate enough electricity for it to carry on regardless. I'm going to go for switching off the fuel pump instead.

The fuel tank certainly does have a breather. On mine it ran in to the driver side rear wheel arch. I will extend it along with the other breathers and add the fuel shut off valve when I build the external cage.

Si