Adding a kill switch. Hard?

[Wee Hooker]

I have a couple of 4-5 hp 20's vintage two stroke outboards that I generally run with a tiller extension on a canoe and rowing skiff. Both of these have the kill switch on or near the cowling vs end of tiller. It's a real PITA and not that safe/fast to get to the switch every time I want to shut the motor down. I was thinking of adding a momentary ( normally open) switch to the end of the tiller extension and some leads running back to a connector on /under the hood. Just not sure where I would connect the wires too. I'm guessing one side gets grounded to the block but the other goes where? Coil? If so, what lead/side? Any input appreciated. Don't want to fry anything.