What a divided response.....I am still of the belief that the Kill switch is the way to go. Since I posted this topic origonally here are my thoughts. I am an electrician, not an auto sparky but your domestic, heavy industrial sparky.
The ignition switch is of the type that sweeps between the contacts (rotary switch) as oposed to the kill switch, it is a fast make and break. When you hit the kill switch a relay is de-energised thus removing any primary voltage to the coil (12V) and the motor stops imediately. This switch also kills any power to the starter control circuit and other dianostic electrics. All this happens in the blink of an eye. With the kill switch off, horn, blinkers, brake lights and any other accessaries still operate.
When using the ignition switch with its inherrent rotary design it is possible to draw an arc across the contacts this in itself can cause excessive current to flow within the circuit, including the ignition coils. It is these high current flows that do the damage not the voltage.
I do not have any drawings of the electrics as yet, and I may be wrong with the ignition switch construction, maybe someone has pulled one apart. I could be wrong about the whole thing and not be subjected to death or serious injury. This is what the good book says..Page 39. When I get my hands on the electrical drawings I will know a lot more or it may be a lot clearer.
On that note can anyone help with drawings, is there a site one can go to????

Thanks all for your comments
OZ Rider (Klagair)