I've used the second style - micro switch on both a Zenoah G62 and a Zenoah GT80 twin with no problems.

On the G62, the throttle pushrod actuated the switch. It was set to be activated at just below idle when flipping a switch on the transmitter. Didn't matter what the throttle setting. Activating the switch moved the servo to low throttle and the switch move the pushrod a tad further, killing the ignition.

Although it was a bit time consuming to set it up just so to ensure proper consistent operation. once done it was great.

The slide switch was wired parallel. That meant that both it and the transmitter switch were required to allow ignition. Either one would kill. That way, there was no chance of anyone just screwing around with the engine and starting it - like spectators can sometimes do.

With the GT 80, I got lazy and just ran it with its own servo, again with the slide switch wired parallel.

In both cases, never a failure.