I changed my suspension system for my Hennessy Hammock and Tarp today. For the hammock i used a standard whoopie sling with 7/64" amsteel blue. For the tarp i wanted to used amsteel blue with a friction knot, but read of people having trouble with it. Heres what i did, and it worked.
I used 7 feet of amsteel blue and put a Locked Brummel on one end. The other end was Back Spliced(#9). I tied a Triple Fishermans Knot in some 150lb guyline to make a loop about 6" in diameter. I used the loop to tie a Klemheist onto the backspliced end of the Tarp Suspension(middle diagram). I tried a variety of prusik's (3 and 4 wraps), but they all slide when pulled taught.
Hope this helps some folks!