I wish I could find the tie strap I saw. I find either or but no combinations. I see where the give would be good but I think I would rather have all cord.
They make other kinds you'll see if you go to tack shops.
The trouble with your using them is that you probably don't have tie points in your trailer... just the posts of the stock trailer structure itself, right? Honestly, if you tie to those with a quick release knot, you need not make it more complicated than that, unless you want to install tie rings.