joehasbeard, A hitch or other knot may actually work better. Or even a toggle and added short line as the WL tarp has pre sewn loops at the ends. We added the stretch lines and mitten hooks when we added the line pockets. But because of the stretch, the tarp will not stay tight on the sides, thus the loose edges in the picture. An adjustable strong line without flex would fix that issue.
The only issue for mods would be the center tie out point. Ours didn't come with them. They were added on. But the guys at WL may add them if you ask. For those that already have the WL Big Daddy and do not want to sew on new tieouts, a tarp clip should work. They make many different brands, most are not that great or designed for thicker plastic tarps. There is a company called easyklip that makes them, super strong, and they sell a mini and micro that seem to work great on tarps. I wouldn't know what long term issues there may be with them as far as wear and damage. Maybe another member can give advise there. check easyklip.com