I'm not sure why you want two switches, one would suffice, but whatever your want is okay. If the toggle switch you pictured is not a momentary switch (only on/off when you hold the toggle) then it and the key switch will be wired in 'series' with the blue wire, preferably. The switch/s will break the circuit thereby shutting off the ignition and stopping the engine.
If I could make a suggestion here; why not use the kill button provided with your kit and then install the keyed switch in the circuit as described above. You would then have a way to shut off the engine easily from the twist grip throttle and you'd have anti-theft protection with the keyed switch. I see no reason for the toggle switch.
Tom