I'm also interested in what others have done on this (I have a 72). I read somewhere of one guy bending the tubs over the frame rather than notching the frame per DSE instructions. Not sure how that worked out.
The end brackets on the upper crossmember are the same. They leave them unwelded so you can modify them to fit the narrowed frame rails required by the DSE kit. If you are looking to buy a 4-link please call me.