I used some 3/4"x 2" steel cut about 6" long and ran it through my homemade 2"x 4" steel bumper to the inside of the frame channel as a shackle mount. They stick out of my bumper about 1 1/2" and I drilled them to accept shackles on the outside while drilling them to align with the big hole in the frame on the inside. This allowed me to bolt it to the frame with 3/4" grade 8 bolts in addition to the four 3/8" bolts at the frame ends. My bumper is more secure and my tow points are incredibly strong. I rounded off the protruding sections with a grinder to make it look more attractive. I know my description here is about as clear as mud, I could take and scan some pics if anyone wants to see them.
"My other car is a BULLDOZER"