I tie my LV down just like the manual says. I squat the suspension a couple inches, with no issues. I have seen the Shock Therapy video, and can't figure out what that guy's problem is! My utility trailer is very tight so it's not going anywhere anyway. All I really need to do is keep it from tipping over and falling off the trailer (12" rails).
In the toy hauler I mostly want to just keep it from sliding back and forth, so I pick the shackles that are furthest away so the straps have a long stretch. No real compression of the suspension.