Where do you folks attach your line lock button?

I used a spare flasher switch from another Dart, and mounted it in my dash next to the wiper switch. A casual glance inside and it looks like it's supposed to be there. Flip it up for "locked" and down for normal driving.
I find it hard to hold the line lock button down with a 4 speed and trying to go from 1st to 2nd without letting it go.

George