Very cool. Did you just put the wire under the fuse?
Ya, same as my grille lights. I have these and those amber grille lights on the same relay. The left leg of the fuse spot, as you're looking down at it with the fuse pulled, is the switched side. So just expose enough of your wire to tuck down in there next to the pole of the position, then push the fuse back down into position just til it's snug. I'm using just a 20g wire since it doesn't take much power at all to trigger the relay.
I'd much rather be able to use an actual fuse tap, but there just isn't a fused spot that is activated with the parking lamp circuit other than F12, which is the box style fuse unfortunately. The main power for the relay is fused of course.