Thank you

I don't like the first 4, but number 4 is legal. I prefer hooking to the belly of the trailer the correct way

Out of the 20 flatbed trailers I used, only 1 had an underneath grip rail. Another one had it but it was too damaged to use. I would guess 90% of flatbedders use the rub rails. I have never heard of a load lost because the straps were cut. Besides, chains only fit on the rub rails because the hooks are too large to catch under rail. If so worried about accidents, then only chains should be used with chain rubs ( garden hose, tire rubber, plastic T, etc).

Thanks for video

Problem with hooking to trailer is you can no longer move winches on that side to help should you need more straps during original tie dow or during your trip. If attached to rub rail, you are able to use winches on that side should you need them. It will also bend your hooks out to where you can no longer fit them between the trailer & rub rail. I'm not arguing the legality, just the practicality. Do it his way. You'll spend 3 to 5 times as long, undoing straps to move winches & have to thread straps through because your hook is stretched out. Try turning a 1 hour strap down into a 5 hour strap down & let me know how that works out for you. Especially on short runs.

My trailer doesn't have a lip to attach to underneath