I considered that, but thought it would be nice to power up with the ignition, but have a switch to power up also if needed....seemed simpler to me at the time. But I guess having the dual throw switch would allow me to keep the power off if I wanted. I don’t have a DT switch right now so I may try the above first, but the more I think about it, the more I like your suggestion better.Get a SPDT switch have the ignition come to one side the battery come to the other and the common pole be connected to the relay.
So you can chose on/off/ignition.