i think a lot of people use the same line they are using on their tarp tie outs, like the orange spectra line from speer hammocks for example.
but it may depend on how much stress you'll be putting on it.
i kinda liked the way ed speer used to do his ridge line (before henesy started harassing him about it). it was just tied to the hammock support on one end, but the other end was a loop that was adjustable with a sliding hitch.
that way you could experiment w/ the sag but it would stay where you decided to leave it.
don`t leave the CREATOR out of the creation!