Cutting the pulldown bar, measure twice cut once!
Creating the attachment point for the pulley system. I made two attachment plates and took the better of the pair.
Next, I welded the attachment plate to the pulldown bar and ground the corners away to create a smooth semi-circle shape.
The final result! I used a ready-made loading pin to put the weight plates on. Then used climbing slings and carabiners to attach the pulleys to my garage rafters. I then used a static climbing rope to connect the whole system with locked bowlines at each end. So far I'm very happy with how it turned out!