I like the under the hood loops idea but my hood fits to tightly. I did add an eyebolt to the frame using an existing hole to provide extra distance from the muffler. ;)  Don't all vehicles have tow hooks front and back as an integral part of the frame?

I have plastic bumpers so I use climbing runners (webbed nylon loops) to spread the pressure on the bumpers. Spring snap chain links attach the runners to the tow hooks and then it's a trucker's hitch to the canoe. The bumpers will move as I cinch down the canoe but the airbag hasn't deployed, yet. :D

Can you do ropes on the front only? I have to balance tension front to back but with a two-door, my rack only has a ~30" spread at best.

I strongly agree that you should be able to rock the car without the canoe pivoting or shifting on the rack whatsoever. Do it half-assed and you could kill people which could easily cut your trip short.