Guys… honestly… just use the dpdt… it’s easy;
Here’s how you wire it up to be self-latching;
Basically you use one of the throws to self-latch, and the other to control whatever you want to control. The diode protects the XAC from current feeding back through the output wire and destroying the XAC. The switch should be the main power switch on the bike or scooter or whatever… so when you turn the main power switch on, the XAC gets power but the relay is dead. Once you scan your authorized chip, the relay will latch and begin feeding itself power, so even if you remove the chip from the XAC antenna it will remain closed. The only way to unlatch it is to cut power via the main switch, but for most vehicle style applications this is totally ok.