It does take some practice to get the hang of, so don't be afraid to tinker with different amounts of sag until you find the right 'zone' for you.
You might actually want to take a length of cord and tie some bowlines on the ends and slip the loops down over each end of your suspension to create a temporary structural ridgeline. That way, you can tinker with the sag in a measured way. Try starting with about 100 inches, give or take. That amount of sag is most comfortable for me. (101" actually)
Once you get used to the amount of sag needed with a ridgeline, you can start eyeballing your hangs to match it, or just leave it in. Personally, I prefer not to use a ridgeline with the ENO, but I did use one when I first got it.