You don't need those. Especially if using a u-haul trailer. Nor do you need them on a regular trailer with d rings and straps. Not if doing it right that is. There's been several threads on here about the easiest and safest way to strap a G-body down.
Many of us do it the same way and it doesn't put the kind of stresses on the frame that t-hooks do.
You need 4 ratchet straps. and I call it the double X method.
You use the fram jack holes already in the frame. There is one behind each front tire, and another in front of each rear wheel each about 2 1/2" in diameter.
Hook a strap into each of the 4 holes, then cross the straps out the front and rear and hook them to the D rings on the trailer.