What I have found to work best is measure your hammock laid flat, find what number is 83% of that then add a few inches in each direction (usually 5" or so) for adjust-ability. This is just what has worked for me and may be different for others. In all honesty if you were to make it adjustable by 10" you should be able to find your sweet spot. Then when you find your sweet spot just mark it measure it and then make a fixed ridgeline off that number.
Formerly known as "Cranky Bear"....
"yesterday is history, tomorrow is a mystery, but today is a gift---thats why its called a present" - Master Oogway
It's always best if your an early riser!
I like hiking as it's like exercise!