I tried the prussik as you suggested. It slipped. I tried it again with the klemheist knot, which held. The klemheist holds and it ties and unties easier.
I then moved on to the woopie and now the UCR. For me the UCR gives the best combination or easy adjustment and length of adjustment.
I have a ring at the hammock ends that serves as a drip stop and ridge line/suspension anchor.