here's my setup...
stock HH line to rings + huggers + biner.
when i turn into ultralight man i'll ditch the biners - but they make it nice and easy for adjusting up or down. i'll make up some longer straps with slightly longer loops to pass the rings through. (i'll also have to get a lighter hammock, lose some weight, get a lighter pack, make some quilts, upgrade my tarp... sigh.)
to tie the line i run it through the rings, then do a sort of HH figure eight 1 time round both rings and add a half hitch.