Grinkle - Wow that was a quick response thanks! The wall is only 6' high so I need to extend it up to cover the slope needed to get the trolley moving. That being said I did plan on using eyebolts with the fold back you mentioned but I will be attaching them to the tubing at approximately 10' on...
I am looking at building a zip line in my back yard and using steel tubing as my end anchors with the following specifications
75' span / support 500lbs at the center / 1/4" steel cable / anchoring the tubing into a 8"x6' masonry wall and encasing it is concrete with an additional 4' of tubing...