It's been a while since I looked at that w/ a tape measure. I'll try to get it out & take measurements tomorrow of what I think would best suit my needs. But the ideal will probably vary according to how you tend to hang your tarp.
I like to hang mine fairly high above the hammock if weather permits.
If you can get a set of Grip Clips, that would be a good way to experiment before sewing.
don`t leave the CREATOR out of the creation!