I symphasize with your rotator cuff. I had surgery on one five years ago. Even with the equipment I have I couldn't get anything cobbled up that seemed right. I've lost the picture but I believe at the far wall I put two pulleys in the ceiling and two pulleys dirrectly under them in the floor about 6 feet apart. For a paddle I had a 6 wide pipe I used as a paddle. Two plastic milk bottles were filled with sand for the right tension and attached to two cable coming down from the ceiling. The cables or (rope)run from the weights to the ceiling, down to the floor pulleys and back to my floor sitting position and attached to the ends of my 6 foot pipe. I hope I'm not telling you wrong but that's the way I remember the setup. It was cheap.

John