RE: Arming switch - advice.
If you believe you are safe using a transmitter switch you are kidding yourself. It just hasn't gone wrong yet....... it may not happen today, tomorrow, next month or next year but it will go wrong! There is no substitute for a physical disconnection (by switch or terminals).
Remember, maximum torque available for the first rotation with electric and a big often carbonfibre "knife" attached.
(Luckily not speaking from direct experience)