All you really need are 4 X 1" washers. Use existing parts from hammock under-frame as pole uprights go low without tarp or add extra poles inserts for added height to attach tarp. Picture shows a ground sheet with predetermined hole spacing for easy setup. Fibre glass tension rods are used to hold hammock down at each end, if desired and can also to provide tarp end uprights, if desired.
BUT - WHO WANTS TO SLEEP ON THE GROUND???