Denis,
You could use something like this:
16A double pole switch.
You could wire it in parallel across both poles for 32Amps which would be more than adequate for the Magic Pie.
If you wired the first position through a 33Ohm resistor, you could use it to pre-charge the capacitors in the controller to eliminate the arcing at the contacts.
Switch it to the position
l (Pre-Charge) for approx 1 second and then switch straight to position
ll (Run) and you're ready to go.
But it will overload and cook the resistor if you try to use the bike with it switched to "
Pre-charge" instead of the "
Run" position.
Perhaps some sort of current limiting device could be used to prevent the resistor from being overloaded.
A switch with a momentary contact for position
l and a latching contact for position
ll would be better.
Alan