Wow, you really are getting into the nitty-gritty.
The wires I fed through using the "push something through the other way that is sturdy enough to hold its shape and attach the new lines" method.
For the contact points, I used 1 of the wires to connect 2 points and see what happened. On my model, there were only 3 likely solder points anyway, so I connected each pair in turn and found the right set. Then I attached the 2 separate wires, 1 to each spot, and those would go to the switch. The fun part was when those wires would dangle next to each other, come into contact and scare the bejezzus out of me when the door opened.
The grips do not need to come off for this install, just the switch housing. That's only a couple of screws. I did change out my grips for other reasons, and they did have to come off for the grip warmers.
If you get to the pictures first, I'll be dissapointed in myself, but glad they're finally up.